Retirement Benefits

12 Months Ended

Dec. 31, 2016

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

Southern Company has a defined benefit, trusteed, pension plan covering substantially all employees, with the exception of employees at Southern Company Gas, as discussed below, and PowerSecure. This qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). On December 19, 2016, the traditional electric operating companies and certain other subsidiaries voluntarily contributed an aggregate of $900 million to Southern Company's qualified pension plan. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2017. Southern Company also provides certain defined benefit pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, Southern Company provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The traditional electric operating companies fund related other postretirement trusts to the extent required by their respective regulatory commissions. For the year ending December 31, 2017, no other postretirement trust contributions are expected.

In addition, Southern Company Gas has a qualified defined benefit, trusteed, pension plan covering certain eligible employees, which was closed in 2012 to new employees. This qualified pension plan is funded in accordance with requirements of ERISA. Southern Company Gas voluntarily contributed $125 million to its qualified pension plan on September 12, 2016. No mandatory contributions to the Southern Company Gas qualified pension plan are anticipated for the year ending December 31, 2017. Southern Company Gas also provides certain non-qualified defined benefit and defined contribution pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, Southern Company Gas provides certain medical care and life insurance benefits for eligible retired employees through a postretirement benefit plan. Southern Company Gas also has a separate unfunded supplemental retirement health care plan that provides medical care and life insurance benefits to employees of discontinued businesses. For the year ending December 31, 2017, no other postretirement trust contributions are expected.

Actuarial Assumptions

The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.

Assumptions used to determine net periodic costs:	2016		2015		2014
Pension plans
Discount rate – benefit obligations	4.58	%	4.17	%	5.02	%
Discount rate – interest costs	3.88		4.17		5.02
Discount rate – service costs	4.98		4.48		5.02
Expected long-term return on plan assets	8.16		8.20		8.20
Annual salary increase	4.37		3.59		3.59
Other postretirement benefit plans
Discount rate – benefit obligations	4.38	%	4.04	%	4.85	%
Discount rate – interest costs	3.66		4.04		4.85
Discount rate – service costs	4.85		4.39		4.85
Expected long-term return on plan assets	6.66		6.97		7.15
Annual salary increase	4.37		3.59		3.59

Assumptions used to determine benefit obligations:	2016		2015
Pension plans
Discount rate	4.40	%	4.67	%
Annual salary increase	4.37		4.46
Other postretirement benefit plans
Discount rate	4.23	%	4.51	%
Annual salary increase	4.37		4.46

The Company estimates the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of seven different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio.

An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO as of December 31, 2016 were as follows:

	Initial Cost Trend Rate		Ultimate Cost Trend Rate		Year That Ultimate Rate is Reached
Pre-65	6.50	%	4.50	%	2025
Post-65 medical	5.00		4.50		2025
Post-65 prescription	10.00		4.50		2025

An annual increase or decrease in the assumed medical care cost trend rate of 1% would affect the APBO and the service and interest cost components at December 31, 2016 as follows:

	1 Percent Increase		1 Percent Decrease
	(in millions)
Benefit obligation	$	128	$	110
Service and interest costs	4		3

Pension Plans

The total accumulated benefit obligation for the pension plans was $11.3 billion at December 31, 2016 and $9.6 billion at December 31, 2015. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	10,542		$	10,909
Acquisitions	1,244			—
Service cost	262			257
Interest cost	422			445
Benefits paid	(466		)	(487		)
Actuarial (gain) loss	381			(582		)
Balance at end of year	12,385			10,542
Change in plan assets
Fair value of plan assets at beginning of year	9,234			9,690
Acquisitions	837			—
Actual return (loss) on plan assets	902			(14		)
Employer contributions	1,076			45
Benefits paid	(466		)	(487		)
Fair value of plan assets at end of year	11,583			9,234
Accrued liability	$	(802	)	$	(1,308	)

At December 31, 2016, the projected benefit obligations for the qualified and non-qualified pension plans were $11.8 billion and $627 million, respectively. All pension plan assets are related to the qualified pension plans.

Amounts presented in the following tables do not include regulatory assets of $369 million recognized by Southern Company Gas associated with its pension plans prior to its acquisition on July 1, 2016.

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's pension plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	3,207		$	2,998
Other current liabilities	(53		)	(46		)
Employee benefit obligations	(749		)	(1,262		)
Other regulatory liabilities, deferred	(87		)	—
Accumulated OCI	100			125

Presented below are the amounts included in accumulated OCI and regulatory assets at December 31, 2016 and 2015 related to the defined benefit pension plans that had not yet been recognized in net periodic pension cost along with the estimated amortization of such amounts for 2017.

	Prior Service Cost		Net (Gain) Loss
	(in millions)
Balance at December 31, 2016:
Accumulated OCI	$	4	$	96
Regulatory assets	51		3,069
Total	$	55	$	3,165
Balance at December 31, 2015:
Accumulated OCI	$	3	$	122
Regulatory assets	27		2,971
Total	$	30	$	3,093
Estimated amortization in net periodic pension cost in 2017:
Accumulated OCI	$	1	$	7
Regulatory assets	11		155
Total	$	12	$	162

The components of OCI and the changes in the balance of regulatory assets related to the defined benefit pension plans for the years ended December 31, 2016 and 2015 are presented in the following table:

	Accumulated OCI			Regulatory Assets
	(in millions)
Balance at December 31, 2014	$	134		$	3,073
Net (gain) loss	1			155
Reclassification adjustments:
Amortization of prior service costs	(1		)	(24		)
Amortization of net gain (loss)	(9		)	(206		)
Total reclassification adjustments	(10		)	(230		)
Total change	(9		)	(75		)
Balance at December 31, 2015	$	125		$	2,998
Net (gain) loss	(20		)	243
Change in prior service costs	2			37
Reclassification adjustments:
Amortization of prior service costs	(1		)	(13		)
Amortization of net gain (loss)	(6		)	(145		)
Total reclassification adjustments	(7		)	(158		)
Total change	(25		)	122
Balance at December 31, 2016	$	100		$	3,120

Components of net periodic pension cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	262		$	257		$	213
Interest cost	422			445			435
Expected return on plan assets	(782		)	(724		)	(645		)
Recognized net (gain) loss	150			215			110
Net amortization	14			25			26
Net periodic pension cost	$	66		$	218		$	139

Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Company has elected to amortize changes in the market value of all plan assets over five years rather than recognize the changes immediately. As a result, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets.

Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	571
2018	593
2019	620
2020	646
2021	666
2022 to 2026	3,673

Other Postretirement Benefits

Changes in the APBO and in the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	1,989		$	1,986
Acquisitions	338			—
Service cost	22			23
Interest cost	76			78
Benefits paid	(119		)	(102		)
Actuarial (gain) loss	(16		)	(38		)
Plan amendments	—			34
Retiree drug subsidy	7			8
Balance at end of year	2,297			1,989
Change in plan assets
Fair value of plan assets at beginning of year	833			900
Acquisitions	100			—
Actual return (loss) on plan assets	58			(12		)
Employer contributions	65			39
Benefits paid	(112		)	(94		)
Fair value of plan assets at end of year	944			833
Accrued liability	$	(1,353	)	$	(1,156	)

Amounts presented in the following tables do not include regulatory assets of $77 million recognized by Southern Company Gas associated with its other postretirement benefit plan prior to its acquisition on July 1, 2016.

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's other postretirement benefit plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	419		$	433
Other current liabilities	(4		)	(4		)
Employee benefit obligations	(1,349		)	(1,152		)
Other regulatory liabilities, deferred	(41		)	(22		)
Accumulated OCI	7			8

Presented below are the amounts included in accumulated OCI and net regulatory assets (liabilities) at December 31, 2016 and 2015 related to the other postretirement benefit plans that had not yet been recognized in net periodic other postretirement benefit cost along with the estimated amortization of such amounts for 2017.

	Prior Service Cost		Net (Gain) Loss
	(in millions)
Balance at December 31, 2016:
Accumulated OCI	$	—	$	7
Net regulatory assets	25		353
Total	$	25	$	360
Balance at December 31, 2015:
Accumulated OCI	$	—	$	8
Net regulatory assets	32		379
Total	$	32	$	387
Estimated amortization as net periodic postretirement benefit cost in 2017:
Net regulatory assets	$	6	$	13

The components of OCI, along with the changes in the balance of net regulatory assets (liabilities), related to the other postretirement benefit plans for the plan years ended December 31, 2016 and 2015 are presented in the following table:

	Accumulated OCI			Net Regulatory Assets (Liabilities)
	(in millions)
Balance at December 31, 2014	$	8		$	366
Net (gain) loss	—			33
Change in prior service costs	—			33
Reclassification adjustments:
Amortization of prior service costs	—			(4		)
Amortization of net gain (loss)	—			(17		)
Total reclassification adjustments	—			(21		)
Total change	—			45
Balance at December 31, 2015	$	8		$	411
Net (gain) loss	(1		)	(13		)
Reclassification adjustments:
Amortization of prior service costs	—			(6		)
Amortization of net gain (loss)	—			(14		)
Total reclassification adjustments	—			(20		)
Total change	(1		)	(33		)
Balance at December 31, 2016	$	7		$	378

Components of the other postretirement benefit plans' net periodic cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	22		$	23		$	21
Interest cost	76			78			79
Expected return on plan assets	(60		)	(58		)	(59		)
Net amortization	21			21			6
Net periodic postretirement benefit cost	$	59		$	64		$	47

Future benefit payments, including prescription drug benefits, reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Estimated benefit payments are reduced by drug subsidy receipts expected as a result of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 as follows:

	Benefit Payments		Subsidy Receipts			Total
	(in millions)
2017	$	145	$	(10	)	$	135
2018	150		(11		)	139
2019	155		(12		)	143
2020	159		(13		)	146
2021	162		(14		)	148
2022 to 2026	823		(73		)	750

Benefit Plan Assets

Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code of 1986, as amended (Internal Revenue Code). The Company's investment policies for both the pension plans and the other postretirement benefit plans cover a diversified mix of assets as described below. Derivative instruments may be used to gain efficient exposure to the various asset classes and as hedging tools. Additionally, the Company minimizes the risk of large losses primarily through diversification but also monitors and manages other aspects of risk.

The investment strategy for plan assets related to the Company's qualified pension plans is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plans is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Southern Company plan employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices.

Investment Strategies and Benefit Plan Asset Fair Values

A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below:

Description	Valuation Methodology
● Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches. ● International equity: A mix of growth stocks and value stocks with both developed and emerging market exposure, managed both actively and through passive index approaches.	Domestic and International equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices are valued as Level 2 when the underlying holdings are comprised of Level 1 or Level 2 equity securities.
● Fixed income: A mix of domestic and international bonds.	Investments in fixed income securities are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.
● Trust-owned life insurance (TOLI): Investments of the Company's taxable trusts aimed at minimizing the impact of taxes on the portfolio.	Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities.
● Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature. ● Real estate: Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities. ● Private equity: Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.	Investments in real estate, private equity, and special situations are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.

The fair values, and actual allocations relative to the target allocations, of Southern Company's pension plan (excluding Southern Company Gas) as of December 31, 2016 and 2015 are presented below. The fair values presented are prepared in accordance with GAAP. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

These fair values exclude cash, receivables related to investment income and pending investment sales, and payables related to pending investment purchases.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient				Target Allocation		Actual Allocation
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	2,010	$	927	$	—	$	—	$	2,937	26	%	29	%
International equity(*)	1,231		1,110		—		—		2,341		25		22
Fixed income:											23		29
U.S. Treasury, government, and agency bonds	—		588		—		—		588
Mortgage- and asset-backed securities	—		13		—		—		13
Corporate bonds	—		991		—		—		991
Pooled funds	—		524		—		—		524
Cash equivalents and other	996		2		—		—		998
Real estate investments	310		—		—		1,152		1,462		14		13
Special situations	—		—				180		180		3		2
Private equity	—		—		—		549		549		9		5
Total	$	4,547	$	4,155	$	—	$	1,881	$	10,583	100	%	100	%

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient					Target Allocation		Actual Allocation
As of December 31, 2015:	(Level 1)			(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(a)	$	1,632		$	681	$	—	$	—	$	2,313		26	%	30	%
International equity(a)	1,190			962		—		—		2,152			25		23
Fixed income:													23		23
U.S. Treasury, government, and agency bonds	—			454		—		—		454
Mortgage- and asset-backed securities	—			199		—		—		199
Corporate bonds	—			1,140		—		—		1,140
Pooled funds	—			500		—		—		500
Cash equivalents and other	—			145		—		—		145
Real estate investments	299			—		—		1,185		1,484			14		16
Special situations(b)	—			—		—		160		160			3		2
Private equity	—			—		—		536		536			9		6
Total	$	3,121		$	4,081	$	—	$	1,881	$	9,083		100	%	100	%
Liabilities:
Derivatives	$	(1	)	$	—	$	—	$	—	$	(1	)
Total	$	3,120		$	4,081	$	—	$	1,881	$	9,082		100	%	100	%

(a) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

(b) The 2015 presentation above has been revised to separately reflect special situations, consistent with the 2016 presentation.

The fair values of Southern Company Gas' pension plan assets for the period ended December 31, 2016 are presented below. The fair value measurements exclude cash, receivables related to investment income, pending investment sales, and payables related to pending investment purchases. For 2016, special situations (absolute return and hedge funds) investment assets are presented in the tables below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	142	$	343	$	—	$	—	$	485
International equity(*)	—		185		—		—		185
Fixed income:
U.S. Treasury, government, and agency bonds	—		85		—		—		85
Corporate bonds	—		41		—		—		41
Pooled funds	—		66		—		—		66
Cash equivalents and other	12		5		—		83		100
Real estate investments	4		—		—		15		19
Private equity	—		—		—		2		2
Total	$	158	$	725	$	—	$	100	$	983

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

The assets of Southern Company Gas' pension plan were allocated 69% equity, 20% fixed income, 1% cash, and 10% other at December 31, 2016, compared to the asset class targets of 53% equity, 15% fixed income, 2% cash, and 30% other. Southern Company Gas' pension plan investment policy provides for variation around the target asset allocation in the form of ranges.

The fair values of Southern Company's (excluding Southern Company Gas) other postretirement benefit plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investment sales, and payables related to pending investment purchases.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient		Total		Target Allocation		Actual Allocation
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)
	(in millions)
Assets:
Domestic equity(*)	$	118	$	28	$	—	$	—	$	146	39	%	40	%
International equity(*)	37		61		—		—		98		23		21
Fixed income:											29		31
U.S. Treasury, government, and agency bonds	—		24		—		—		24
Corporate bonds	—		30		—		—		30
Pooled funds	—		49		—		—		49
Cash equivalents and other	41		—		—		—		41
Trust-owned life insurance	—		382		—		—		382
Real estate investments	11		—		—		35		46		5		5
Special situations	—		—		—		5		5		1		1
Private equity	—		—		—		17		17		3		2
Total	$	207	$	574	$	—	$	57	$	838	100	%	100	%

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient				Target Allocation		Actual Allocation
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(a)	$	106	$	52	$	—	$	—	$	158	42	%	38	%
International equity(a)	40		63		—		—		103		21		23
Fixed income:											28		30
U.S. Treasury, government, and agency bonds	—		22		—		—		22
Mortgage- and asset-backed securities	—		7		—		—		7
Corporate bonds	—		38		—		—		38
Pooled funds	—		42		—		—		42
Cash equivalents and other	11		9		—		—		20
Trust-owned life insurance	—		370		—		—		370
Real estate investments	11		—		—		40		51		5		6
Special situations(b)	—		—		—		5		5		1		1
Private equity	—		—		—		18		18		3		2
Total	$	168	$	603	$	—	$	63	$	834	100	%	100	%

(a) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

(b) The 2015 presentation above has been revised to separately reflect special situations, consistent with the 2016 presentation.

The fair values of Southern Company Gas' other postretirement benefit plan assets for the period ended December 31, 2016 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investment sales, and payables related to pending investment purchases. For 2016, special situations (absolute return and hedge funds) investment assets are presented in the tables below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient		Total
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)
	(in millions)
Assets:
Domestic equity(*)	$	3	$	58	$	—	$	—	$	61
International equity(*)	—		18		—		—		18
Fixed income:
Pooled funds	—		23		—		—		23
Cash equivalents and other	1		—		—		2		3
Total	$	4	$	99	$	—	$	2	$	105

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

The assets of Southern Company Gas' other postretirement benefit plans were allocated 74% equity, 23% fixed income, 1% cash, and 2% other at December 31, 2016, compared to the asset class targets of 72% equity, 24% fixed income, 1% cash, and 3% other. Southern Company Gas' other postretirement plan's investment policy provides for some variation in these targets in the form of ranges around the target.

Employee Savings Plan

Southern Company and its subsidiaries also sponsor 401(k) defined contribution plans covering substantially all employees and provide matching contributions up to specified percentages of an employee's eligible pay. Total matching contributions made to the plans for 2016, 2015, and 2014 were $105 million, $92 million, and $87 million, respectively.

Alabama Power [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

The Company has a defined benefit, trusteed, pension plan covering substantially all employees. This qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). On December 19, 2016, the Company voluntarily contributed $129 million to the qualified pension plan. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2017. The Company also provides certain defined benefit pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, the Company provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The Company funds its other postretirement trusts to the extent required by the Alabama PSC and the FERC. For the year ending December 31, 2017, no other postretirement trusts contributions are expected.

Actuarial Assumptions

The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.

Assumptions used to determine net periodic costs:	2016		2015		2014
Pension plans
Discount rate – benefit obligations	4.67	%	4.18	%	5.02	%
Discount rate – interest costs	3.90		4.18		5.02
Discount rate – service costs	5.07		4.49		5.02
Expected long-term return on plan assets	8.20		8.20		8.20
Annual salary increase	4.46		3.59		3.59
Other postretirement benefit plans
Discount rate – benefit obligations	4.51	%	4.04	%	4.86	%
Discount rate – interest costs	3.69		4.04		4.86
Discount rate – service costs	4.96		4.40		4.86
Expected long-term return on plan assets	6.83		7.17		7.34
Annual salary increase	4.46		3.59		3.59

Assumptions used to determine benefit obligations:	2016		2015
Pension plans
Discount rate	4.44	%	4.67	%
Annual salary increase	4.46		4.46
Other postretirement benefit plans
Discount rate	4.27	%	4.51	%
Annual salary increase	4.46		4.46

The Company estimates the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of seven different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio.

An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO as of December 31, 2016 were as follows:

	Initial Cost Trend Rate		Ultimate Cost Trend Rate		Year That Ultimate Rate is Reached
Pre-65	6.50	%	4.50	%	2025
Post-65 medical	5.00		4.50		2025
Post-65 prescription	10.00		4.50		2025

An annual increase or decrease in the assumed medical care cost trend rate of 1% would affect the APBO and the service and interest cost components at December 31, 2016 as follows:

	1 Percent Increase		1 Percent Decrease
	(in millions)
Benefit obligation	$	28	$	24
Service and interest costs	1		1

Pension Plans

The total accumulated benefit obligation for the pension plans was $2.4 billion at December 31, 2016 and $2.3 billion at December 31, 2015. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	2,506		$	2,592
Service cost	57			59
Interest cost	95			106
Benefits paid	(109		)	(120		)
Actuarial (gain) loss	114			(131		)
Balance at end of year	2,663			2,506
Change in plan assets
Fair value of plan assets at beginning of year	2,279			2,396
Actual return (loss) on plan assets	206			(9		)
Employer contributions	141			12
Benefits paid	(109		)	(120		)
Fair value of plan assets at end of year	2,517			2,279
Accrued liability	$	(146	)	$	(227	)

At December 31, 2016, the projected benefit obligations for the qualified and non-qualified pension plans were $2.5 billion and $124 million, respectively. All pension plan assets are related to the qualified pension plan.

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's pension plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	870		$	822
Other current liabilities	(12		)	(11		)
Employee benefit obligations	(134		)	(216		)

Presented below are the amounts included in regulatory assets at December 31, 2016 and 2015 related to the defined benefit pension plans that had not yet been recognized in net periodic pension cost along with the estimated amortization of such amounts for 2017.

	2016		2015		Estimated Amortization in 2017
	(in millions)
Prior service cost	$	10	$	6	$	3
Net (gain) loss	860		816		42
Regulatory assets	$	870	$	822

The changes in the balance of regulatory assets related to the defined benefit pension plans for the years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Regulatory assets:
Beginning balance	$	822		$	827
Net (gain) loss	84			56
Change in prior service costs	7			—
Reclassification adjustments:
Amortization of prior service costs	(3		)	(6		)
Amortization of net gain (loss)	(40		)	(55		)
Total reclassification adjustments	(43		)	(61		)
Total change	48			(5		)
Ending balance	$	870		$	822

Components of net periodic pension cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	57		$	59		$	48
Interest cost	95			106			103
Expected return on plan assets	(184		)	(178		)	(168		)
Recognized net (gain) loss	40			55			31
Net amortization	3			6			7
Net periodic pension cost	$	11		$	48		$	21

Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Company has elected to amortize changes in the market value of all plan assets over five years rather than recognize the changes immediately. As a result, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets.

Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	122
2018	127
2019	132
2020	137
2021	142
2022 to 2026	777

Other Postretirement Benefits

Changes in the APBO and in the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	505		$	503
Service cost	5			6
Interest cost	18			20
Benefits paid	(28		)	(27		)
Actuarial (gain) loss	(1		)	(7		)
Plan amendment	—			7
Retiree drug subsidy	2			3
Balance at end of year	501			505
Change in plan assets
Fair value of plan assets at beginning of year	363			392
Actual return (loss) on plan assets	23			(6		)
Employer contributions	7			1
Benefits paid	(26		)	(24		)
Fair value of plan assets at end of year	367			363
Accrued liability	$	(134	)	$	(142	)

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's other postretirement benefit plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	86		$	95
Other regulatory liabilities, deferred	(10		)	(13		)
Employee benefit obligations	(134		)	(142		)

Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2016 and 2015 related to the other postretirement benefit plans that had not yet been recognized in net periodic other postretirement benefit cost along with the estimated amortization of such amounts for 2017.

	2016		2015		Estimated Amortization in 2017
	(in millions)
Prior service cost	$	15	$	19	$	4
Net (gain) loss	61		63		1
Net regulatory assets	$	76	$	82

The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Net regulatory assets (liabilities):
Beginning balance	$	82		$	54
Net (gain) loss	—			25
Change in prior service costs	—			8
Reclassification adjustments:
Amortization of prior service costs	(4		)	(3		)
Amortization of net gain (loss)	(2		)	(2		)
Total reclassification adjustments	(6		)	(5		)
Total change	(6		)	28
Ending balance	$	76		$	82

Components of the other postretirement benefit plans' net periodic cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	5		$	6		$	5
Interest cost	18			20			20
Expected return on plan assets	(25		)	(26		)	(25		)
Net amortization	6			5			4
Net periodic postretirement benefit cost	$	4		$	5		$	4

Future benefit payments, including prescription drug benefits, reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Estimated benefit payments are reduced by drug subsidy receipts expected as a result of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 as follows:

	Benefit Payments		Subsidy Receipts			Total
	(in millions)
2017	$	32	$	(3	)	$	29
2018	33		(3		)	30
2019	34		(4		)	30
2020	35		(4		)	31
2021	36		(4		)	32
2022 to 2026	183		(22		)	161

Benefit Plan Assets

Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code of 1986, as amended. The Company's investment policies for both the pension plan and the other postretirement benefit plans cover a diversified mix of assets, including equity and fixed income securities, real estate, and private equity. Derivative instruments are used primarily to gain efficient exposure to the various asset classes and as hedging tools. The Company minimizes the risk of large losses primarily through diversification but also monitors and manages other aspects of risk.

The composition of the Company's pension plan and other postretirement benefit plan assets as of December 31, 2016 and 2015, along with the targeted mix of assets for each plan, is presented below:

	Target		2016		2015
Pension plan assets:
Domestic equity	26	%	29	%	30	%
International equity	25		22		23
Fixed income	23		29		23
Special situations	3		2		2
Real estate investments	14		13		16
Private equity	9		5		6
Total	100	%	100	%	100	%
Other postretirement benefit plan assets:
Domestic equity	46	%	44	%	45	%
International equity	22		20		20
Domestic fixed income	24		29		27
Special situations	1		1		1
Real estate investments	4		4		5
Private equity	3		2		2
Total	100	%	100	%	100	%

The investment strategy for plan assets related to the Company's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Company employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices.

Investment Strategies

Detailed below is a description of the investment strategies for each major asset category for the pension and other postretirement benefit plans disclosed above:

• Domestic equity. A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

• International equity. A mix of growth stocks and value stocks with both developed and emerging market exposure, managed both actively and through passive index approaches.

• Fixed income. A mix of domestic and international bonds.

• Trust-owned life insurance (TOLI). Investments of the Company's taxable trusts aimed at minimizing the impact of taxes on the portfolio.

• Special situations. Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies as well as investments in promising new strategies of a longer-term nature.

• Real estate investments. Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities.

• Private equity. Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

Benefit Plan Asset Fair Values

Following are the fair value measurements for the pension plan and the other postretirement benefit plan assets as of December 31, 2016 and 2015. The fair values presented are prepared in accordance with GAAP. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

Valuation methods of the primary fair value measurements disclosed in the following tables are as follows:

• Domestic and international equity.Investments in equity securities such as common stocks, American depositary receipts, and real estate investment trusts that trade on a public exchange are classified as Level 1 investments and are valued at the closing price in the active market. Equity investments with unpublished prices (i.e. pooled funds) are valued as Level 2, when the underlying holdings used to value the investment are comprised of Level 1 or Level 2 equity securities.

• Fixed income.Investments in fixed income securities are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.

• TOLI. Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate account. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities.

• Real estate investments, private equity, and special situations investments.Investments in real estate, private equity, and special situations are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.

The fair values of pension plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2015, investments in special situations were presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	477	$	220	$	—	$	—	$	697
International equity(*)	292		264		—		—		556
Fixed income:
U.S. Treasury, government, and agency bonds	—		140		—		—		140
Mortgage- and asset-backed securities	—		3		—		—		3
Corporate bonds	—		235		—		—		235
Pooled funds	—		124		—		—		124
Cash equivalents and other	236		1		—		—		237
Real estate investments	74		—		—		274		348
Special situations	—		—		—		43		43
Private equity	—		—		—		130		130
Total	$	1,079	$	987	$	—	$	447	$	2,513

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	403	$	168	$	—	$	—	$	571
International equity(*)	294		244		—		—		538
Fixed income:
U.S. Treasury, government, and agency bonds	—		112		—		—		112
Mortgage- and asset-backed securities	—		49		—		—		49
Corporate bonds	—		280		—		—		280
Pooled funds	—		123		—		—		123
Cash equivalents and other	—		36		—		—		36
Real estate investments	74		—		—		301		375
Private equity	—		—		—		157		157
Total	$	771	$	1,012	$	—	$	458	$	2,241

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

The fair values of other postretirement benefit plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2015, investments in special situations were presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	51	$	10	$	—	$	—	$	61
International equity(*)	13		12		—		—		25
Fixed income:
U.S. Treasury, government, and agency bonds	—		7		—		—		7
Mortgage- and asset-backed securities	—		—		—		—		—
Corporate bonds	—		10		—		—		10
Pooled funds	—		5		—		—		5
Cash equivalents and other	14		—		—		—		14
Trust-owned life insurance	—		220		—		—		220
Real estate investments	4		—		—		12		16
Special situations	—		—		—		2		2
Private equity	—		—		—		6		6
Total	$	82	$	264	$	—	$	20	$	366

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	57	$	8	$	—	$	—	$	65
International equity(*)	14		12		—		—		26
Fixed income:
U.S. Treasury, government, and agency bonds	—		8		—		—		8
Mortgage- and asset-backed securities	—		2		—		—		2
Corporate bonds	—		13		—		—		13
Pooled funds	—		6		—		—		6
Cash equivalents and other	1		2		—		—		3
Trust-owned life insurance	—		212		—		—		212
Real estate investments	5		—		—		14		19
Private equity	—		—		—		7		7
Total	$	77	$	263	$	—	$	21	$	361

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

Employee Savings Plan

The Company also sponsors a 401(k) defined contribution plan covering substantially all employees. The Company provides an 85% matching contribution on up to 6% of an employee's base salary. Total matching contributions made to the plan for 2016, 2015, and 2014 were $23 million, $22 million, and $21 million, respectively.

Georgia Power [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

The Company has a defined benefit, trusteed, pension plan covering substantially all employees. This qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). On December 19, 2016, the Company voluntarily contributed $287 million to the qualified pension plan. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2017. The Company also provides certain defined benefit pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, the Company provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The Company funds its other postretirement trusts to the extent required by the Georgia PSC and the FERC. For the year ending December 31, 2017, no other postretirement trust contributions are expected.

Actuarial Assumptions

The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.

Assumptions used to determine net periodic costs:	2016		2015		2014
Pension plans
Discount rate – benefit obligations	4.65	%	4.18	%	5.02	%
Discount rate – interest costs	3.86		4.18		5.02
Discount rate – service costs	5.03		4.49		5.02
Expected long-term return on plan assets	8.20		8.20		8.20
Annual salary increase	4.46		3.59		3.59
Other postretirement benefit plans
Discount rate – benefit obligations	4.49	%	4.03	%	4.85	%
Discount rate – interest costs	3.67		4.03		4.85
Discount rate – service costs	4.88		4.39		4.85
Expected long-term return on plan assets	6.27		6.48		6.75
Annual salary increase	4.46		3.59		3.59

Assumptions used to determine benefit obligations:	2016		2015
Pension plans
Discount rate	4.40	%	4.65	%
Annual salary increase	4.46		4.46
Other postretirement benefit plans
Discount rate	4.23	%	4.49	%
Annual salary increase	4.46		4.46

The Company estimates the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of seven different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio.

An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO as of December 31, 2016 were as follows:

	Initial Cost Trend Rate		Ultimate Cost Trend Rate		Year That Ultimate Rate is Reached
Pre-65	6.50	%	4.50	%	2025
Post-65 medical	5.00		4.50		2025
Post-65 prescription	10.00		4.50		2025

An annual increase or decrease in the assumed medical care cost trend rate of 1% would affect the APBO and the service and interest cost components at December 31, 2016 as follows:

	1 Percent Increase		1 Percent Decrease
	(in millions)
Benefit obligation	$	55	$	48
Service and interest costs	2		2

Pension Plans

The total accumulated benefit obligation for the pension plans was $3.5 billion at December 31, 2016 and $3.3 billion at December 31, 2015. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	3,615		$	3,781
Service cost	70			73
Interest cost	136			154
Benefits paid	(164		)	(188		)
Actuarial (gain) loss	143			(205		)
Balance at end of year	3,800			3,615
Change in plan assets
Fair value of plan assets at beginning of year	3,196			3,383
Actual return (loss) on plan assets	288			(13		)
Employer contributions	301			14
Benefits paid	(164		)	(188		)
Fair value of plan assets at end of year	3,621			3,196
Accrued liability	$	(179	)	$	(419	)

At December 31, 2016, the projected benefit obligations for the qualified and non-qualified pension plans were $3.6 billion and $152 million, respectively. All pension plan assets are related to the qualified pension plan.

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's pension plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	1,129		$	1,076
Other current liabilities	(14		)	(13		)
Employee benefit obligations	(165		)	(406		)

Presented below are the amounts included in regulatory assets at December 31, 2016 and 2015 related to the defined benefit pension plans that had not yet been recognized in net periodic pension cost along with the estimated amortization of such amounts for 2017.

	2016		2015		Estimated Amortization in 2017
	(in millions)
Prior service cost	$	17	$	8	$	3
Net (gain) loss	1,112		1,068		57
Regulatory assets	$	1,129	$	1,076

The changes in the balance of regulatory assets related to the defined benefit pension plans for the years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Regulatory assets:
Beginning balance	$	1,076		$	1,102
Net (gain) loss	99			59
Change in prior service costs	14			—
Reclassification adjustments:
Amortization of prior service costs	(5		)	(9		)
Amortization of net gain (loss)	(55		)	(76		)
Total reclassification adjustments	(60		)	(85		)
Total change	53			(26		)
Ending balance	$	1,129		$	1,076

Components of net periodic pension cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	70		$	73		$	62
Interest cost	136			154			153
Expected return on plan assets	(258		)	(251		)	(228		)
Recognized net (gain) loss	55			76			41
Net amortization	5			9			10
Net periodic pension cost	$	8		$	61		$	38

Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Company has elected to amortize changes in the market value of all plan assets over five years rather than recognize the changes immediately. As a result, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets.

Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	184
2018	190
2019	196
2020	202
2021	206
2022 to 2026	1,126

Other Postretirement Benefits

Changes in the APBO and in the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	854		$	864
Service cost	6			7
Interest cost	30			34
Benefits paid	(45		)	(45		)
Actuarial (gain) loss	(1		)	(22		)
Plan amendment	—			12
Retiree drug subsidy	3			4
Balance at end of year	847			854
Change in plan assets
Fair value of plan assets at beginning of year	358			395
Actual return (loss) on plan assets	21			(6		)
Employer contributions	17			10
Benefits paid	(42		)	(41		)
Fair value of plan assets at end of year	354			358
Accrued liability	$	(493	)	$	(496	)

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's other postretirement benefit plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	213		$	223
Employee benefit obligations	(493		)	(496		)

Presented below are the amounts included in regulatory assets at December 31, 2016 and 2015 related to the other postretirement benefit plans that had not yet been recognized in net periodic other postretirement benefit cost along with the estimated amortization of such amounts for 2017.

	2016		2015		Estimated Amortization in 2017
	(in millions)
Prior service cost	$	6	$	8	$	1
Net (gain) loss	207		215		8
Regulatory assets	$	213	$	223

The changes in the balance of regulatory assets related to the other postretirement benefit plans for the plan years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Regulatory assets:
Beginning balance	$	223		$	213
Net (gain) loss	—			9
Change in prior service costs	—			12
Reclassification adjustments:
Amortization of prior service costs	(1		)	—
Amortization of net gain (loss)	(9		)	(11		)
Total reclassification adjustments	(10		)	(11		)
Total change	(10		)	10
Ending balance	$	213		$	223

Components of the other postretirement benefit plans' net periodic cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	6		$	7		$	6
Interest cost	30			34			34
Expected return on plan assets	(22		)	(24		)	(25		)
Net amortization	10			11			2
Net periodic postretirement benefit cost	$	24		$	28		$	17

Future benefit payments, including prescription drug benefits, reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Estimated benefit payments are reduced by drug subsidy receipts expected as a result of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 as follows:

	Benefit Payments		Subsidy Receipts			Total
	(in millions)
2017	$	54	$	(4	)	$	50
2018	56		(5		)	51
2019	58		(5		)	53
2020	59		(5		)	54
2021	60		(6		)	54
2022 to 2026	303		(32		)	271

Benefit Plan Assets

Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code of 1986, as amended. The Company's investment policies for both the pension plan and the other postretirement benefit plans cover a diversified mix of assets, including equity and fixed income securities, real estate, and private equity. Derivative instruments are used primarily to gain efficient exposure to the various asset classes and as hedging tools. The Company minimizes the risk of large losses primarily through diversification but also monitors and manages other aspects of risk.

The composition of the Company's pension plan and other postretirement benefit plan assets as of December 31, 2016 and 2015, along with the targeted mix of assets for each plan, is presented below:

	Target		2016		2015
Pension plan assets:
Domestic equity	26	%	29	%	30	%
International equity	25		22		23
Fixed income	23		29		23
Special situations	3		2		2
Real estate investments	14		13		16
Private equity	9		5		6
Total	100	%	100	%	100	%
Other postretirement benefit plan assets:
Domestic equity	36	%	35	%	34	%
International equity	24		24		27
Domestic fixed income	33		35		25
Global fixed income					8
Special situations	1		1		—
Real estate investments	4		4		4
Private equity	2		1		2
Total	100	%	100	%	100	%

The investment strategy for plan assets related to the Company's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Company employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices.

Investment Strategies

Detailed below is a description of the investment strategies for each major asset category for the pension and other postretirement benefit plans disclosed above:

• Domestic equity. A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

• International equity. A mix of growth stocks and value stocks with both developed and emerging market exposure, managed both actively and through passive index approaches.

• Fixed income. A mix of domestic and international bonds.

• Trust-owned life insurance (TOLI). Investments of the Company's taxable trusts aimed at minimizing the impact of taxes on the portfolio.

• Special situations. Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies as well as investments in promising new strategies of a longer-term nature.

• Real estate investments. Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities.

• Private equity. Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

Benefit Plan Asset Fair Values

Following are the fair value measurements for the pension plan and the other postretirement benefit plan assets as of December 31, 2016 and 2015. The fair values presented are prepared in accordance with GAAP. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

Valuation methods of the primary fair value measurements disclosed in the following tables are as follows:

• Domestic and international equity.Investments in equity securities such as common stocks, American depositary receipts, and real estate investment trusts that trade on a public exchange are classified as Level 1 investments and are valued at the closing price in the active market. Equity investments with unpublished prices (i.e. pooled funds) are valued as Level 2, when the underlying holdings used to value the investment are comprised of Level 1 or Level 2 equity securities.

• Fixed income.Investments in fixed income securities are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.

• TOLI. Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate account. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities.

• Real estate investments, private equity, and special situations investments.Investments in real estate, private equity, and special situations are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.

The fair values of pension plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2015, investments in special situations were presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	686	$	317	$	—	$	—	$	1,003
International equity(*)	420		380		—		—		800
Fixed income:
U.S. Treasury, government, and agency bonds	—		201		—		—		201
Mortgage- and asset-backed securities	—		4		—		—		4
Corporate bonds	—		338		—		—		338
Pooled funds	—		179		—		—		179
Cash equivalents and other	340		1		—		—		341
Real estate investments	106		—		—		394		500
Special situations	—		—		—		61		61
Private equity	—		—		—		188		188
Total	$	1,552	$	1,420	$	—	$	643	$	3,615

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	565	$	236	$	—	$	—	$	801
International equity(*)	412		343		—		—		755
Fixed income:
U.S. Treasury, government, and agency bonds	—		157		—		—		157
Mortgage- and asset-backed securities	—		69		—		—		69
Corporate bonds	—		394		—		—		394
Pooled funds	—		173		—		—		173
Cash equivalents and other	—		50		—		—		50
Real estate investments	103		—		—		421		524
Private equity	—		—		—		220		220
Total	$	1,080	$	1,422	$	—	$	641	$	3,143

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

The fair values of other postretirement benefit plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2015, investments in special situations were presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	45	$	9	$	—	$	—	$	54
International equity(*)	11		37		—		—		48
Fixed income:
U.S. Treasury, government, and agency bonds	—		5		—		—		5
Mortgage- and asset-backed securities	—		—		—		—		—
Corporate bonds	—		9		—		—		9
Pooled funds	—		38		—		—		38
Cash equivalents and other	15		—		—		—		15
Trust-owned life insurance	—		162		—		—		162
Real estate investments	3		—		—		11		14
Special situations	—		—		—		2		2
Private equity	—		—		—		5		5
Total	$	74	$	260	$	—	$	18	$	352

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	30	$	36	$	—	$	—	$	66
International equity(*)	12		41		—		—		53
Fixed income:
U.S. Treasury, government, and agency  bonds	—		5		—		—		5
Mortgage- and asset-backed securities	—		2		—		—		2
Corporate bonds	—		12		—		—		12
Pooled funds	—		30		—		—		30
Cash equivalents and other	10		6		—		—		16
Trust-owned life insurance	—		158		—		—		158
Real estate investments	3		—		—		12		15
Private equity	—		—		—		7		7
Total	$	55	$	290	$	—	$	19	$	364

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

Employee Savings Plan

The Company also sponsors a 401(k) defined contribution plan covering substantially all employees. The Company provides an 85% matching contribution on up to 6% of an employee's base salary. Total matching contributions made to the plan for 2016, 2015, and 2014 were $27 million, $26 million, and $25 million, respectively.

Gulf Power [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

The Company has a defined benefit, trusteed, pension plan covering substantially all employees. This qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). On December 19, 2016, the Company voluntarily contributed $48 million to the qualified pension plan. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2017. The Company also provides certain defined benefit pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, the Company provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The Company funds its other postretirement trusts to the extent required by the FERC. For the year ending December 31, 2017, no other postretirement trust contributions are expected.

Actuarial Assumptions

The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.

Assumptions used to determine net periodic costs:	2016		2015		2014
Pension plans
Discount rate – benefit obligations	4.71	%	4.18	%	5.02	%
Discount rate – interest costs	3.97		4.18		5.02
Discount rate – service costs	5.04		4.48		5.02
Expected long-term return on plan assets	8.20		8.20		8.20
Annual salary increase	4.46		3.59		3.59
Other postretirement benefit plans
Discount rate – benefit obligations	4.51	%	4.04	%	4.86	%
Discount rate – interest costs	3.68		4.04		4.86
Discount rate – service costs	4.88		4.38		4.86
Expected long-term return on plan assets	8.05		8.07		8.08
Annual salary increase	4.46		3.59		3.59

Assumptions used to determine benefit obligations:	2016		2015
Pension plans
Discount rate	4.46	%	4.71	%
Annual salary increase	4.46		4.46
Other postretirement benefit plans
Discount rate	4.25	%	4.51	%
Annual salary increase	4.46		4.46

The Company estimates the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of seven different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio.

An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO as of December 31, 2016 were as follows:

	Initial Cost Trend Rate		Ultimate Cost Trend Rate		Year That Ultimate Rate is Reached
Pre-65	6.50	%	4.50	%	2025
Post-65 medical	5.00		4.50		2025
Post-65 prescription	10.00		4.50		2025

An annual increase or decrease in the assumed medical care cost trend rate of 1% would affect the APBO and the service and interest cost components at December 31, 2016 as follows:

	1 Percent Increase		1 Percent Decrease
	(in millions)
Benefit obligation	$	4	$	3
Service and interest costs	—		—

Pension Plans

The total accumulated benefit obligation for the pension plans was $460 million at December 31, 2016 and $424 million at December 31, 2015. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	480		$	491
Service cost	12			12
Interest cost	19			20
Benefits paid	(17		)	(20		)
Actuarial (gain) loss	23			(23		)
Balance at end of year	517			480
Change in plan assets
Fair value of plan assets at beginning of year	420			435
Actual return (loss) on plan assets	39			4
Employer contributions	49			1
Benefits paid	(17		)	(20		)
Fair value of plan assets at end of year	491			420
Accrued liability	$	(26	)	$	(60	)

At December 31, 2016, the projected benefit obligations for the qualified and non-qualified pension plans were $494 million and $23 million, respectively. All pension plan assets are related to the qualified pension plan.

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's pension plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	153		$	142
Other current liabilities	(1		)	(1		)
Employee benefit obligations	(25		)	(59		)

Presented below are the amounts included in regulatory assets at December 31, 2016 and 2015 related to the defined benefit pension plans that had not yet been recognized in net periodic pension cost along with the estimated amortization of such amounts for 2017.

	2016		2015		Estimated Amortization in 2017
	(in millions)
Prior service cost	$	3	$	2	$	1
Net (gain) loss	150		140		7
Regulatory assets	$	153	$	142

The changes in the balance of regulatory assets related to the defined benefit pension plans for the years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Regulatory assets:
Beginning balance	$	142		$	146
Net (gain) loss	16			6
Change in prior service costs	2			—
Reclassification adjustments:
Amortization of prior service costs	(1		)	(1		)
Amortization of net gain (loss)	(6		)	(9		)
Total reclassification adjustments	(7		)	(10		)
Total change	11			(4		)
Ending balance	$	153		$	142

Components of net periodic pension cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	12		$	12		$	10
Interest cost	19			20			19
Expected return on plan assets	(34		)	(32		)	(28		)
Recognized net (gain) loss	6			9			5
Net amortization	1			1			1
Net periodic pension cost	$	4		$	10		$	7

Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Company has elected to amortize changes in the market value of all plan assets over five years rather than recognize the changes immediately. As a result, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets.

Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	20
2018	22
2019	23
2020	24
2021	26
2022 to 2026	149

Other Postretirement Benefits

Changes in the APBO and in the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	81		$	78
Service cost	1			1
Interest cost	3			3
Benefits paid	(4		)	(4		)
Actuarial (gain) loss	2			(1		)
Plan amendment	—			4
Balance at end of year	83			81
Change in plan assets
Fair value of plan assets at beginning of year	17			18
Actual return (loss) on plan assets	2			—
Employer contributions	3			3
Benefits paid	(4		)	(4		)
Fair value of plan assets at end of year	18			17
Accrued liability	$	(65	)	$	(64	)

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's other postretirement benefit plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	11		$	10
Other current liabilities	(1		)	(1		)
Other regulatory liabilities, deferred	(4		)	(5		)
Employee benefit obligations	(64		)	(63		)

Approximately $7 million and $5 million was included in net regulatory assets at December 31, 2016 and 2015, respectively, related to the net loss for the other postretirement benefit plans that had not yet been recognized in net periodic other postretirement benefit cost. The estimated amortization of such amounts for 2017 is immaterial.

The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2016 and 2015 are presented in the following table:

	2016		2015
	(in millions)
Net regulatory assets (liabilities):
Beginning balance	$	5	$	2
Net (gain) loss	2		1
Change in prior service costs	—		2
Total change	2		3
Ending balance	$	7	$	5

Components of the other postretirement benefit plans' net periodic cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	1		$	1		$	1
Interest cost	3			3			3
Expected return on plan assets	(1		)	(1		)	(1		)
Net periodic postretirement benefit cost	$	3		$	3		$	3

Future benefit payments, including prescription drug benefits, reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Estimated benefit payments are reduced by drug subsidy receipts expected as a result of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 as follows:

	Benefit Payments		Subsidy Receipts			Total
	(in millions)
2017	$	5	$	—		$	5
2018	5		—			5
2019	6		(1		)	5
2020	6		(1		)	5
2021	6		(1		)	5
2022 to 2026	30		(3		)	27

Benefit Plan Assets

Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code of 1986, as amended. The Company's investment policies for both the pension plan and the other postretirement benefit plans cover a diversified mix of assets, including equity and fixed income securities, real estate, and private equity. Derivative instruments are used primarily to gain efficient exposure to the various asset classes and as hedging tools. The Company minimizes the risk of large losses primarily through diversification but also monitors and manages other aspects of risk.

The composition of the Company's pension plan and other postretirement benefit plan assets as of December 31, 2016 and 2015, along with the targeted mix of assets for each plan, is presented below:

	Target		2016		2015
Pension plan assets:
Domestic equity	26	%	29	%	30	%
International equity	25		22		23
Fixed income	23		29		23
Special situations	3		2		2
Real estate investments	14		13		16
Private equity	9		5		6
Total	100	%	100	%	100	%
Other postretirement benefit plan assets:
Domestic equity	25	%	28	%	29	%
International equity	24		21		22
Domestic fixed income	25		31		25
Special situations	3		2		2
Real estate investments	14		13		16
Private equity	9		5		6
Total	100	%	100	%	100	%

The investment strategy for plan assets related to the Company's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Company employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices.

Investment Strategies

Detailed below is a description of the investment strategies for each major asset category for the pension and other postretirement benefit plans disclosed above:

• Domestic equity. A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

• International equity. A mix of growth stocks and value stocks with both developed and emerging market exposure, managed both actively and through passive index approaches.

• Fixed income. A mix of domestic and international bonds.

• Special situations. Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies as well as investments in promising new strategies of a longer-term nature.

• Real estate investments. Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities.

• Private equity. Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

Benefit Plan Asset Fair Values

Following are the fair value measurements for the pension plan and the other postretirement benefit plan assets as of December 31, 2016 and 2015. The fair values presented are prepared in accordance with GAAP. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

Valuation methods of the primary fair value measurements disclosed in the following tables are as follows:

• Domestic and international equity.Investments in equity securities such as common stocks, American depositary receipts, and real estate investment trusts that trade on a public exchange are classified as Level 1 investments and are valued at the closing price in the active market. Equity investments with unpublished prices (i.e. pooled funds) are valued as Level 2, when the underlying holdings used to value the investment are comprised of Level 1 or Level 2 equity securities.

• Fixed income.Investments in fixed income securities are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.

• Real estate investments, private equity, and special situations investments.Investments in real estate, private equity, and special situations are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.

The fair values of pension plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2015, investments in special situations were presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	93	$	43	$	—	$	—	$	136
International equity(*)	57		52		—		—		109
Fixed income:
U.S. Treasury, government, and agency bonds	—		27		—		—		27
Mortgage- and asset-backed securities	—		1		—		—		1
Corporate bonds	—		47		—		—		47
Pooled funds	—		24		—		—		24
Cash equivalents and other	46		—		—		—		46
Real estate investments	14		—		—		53		67
Special situations	—		—		—		8		8
Private equity	—		—		—		25		25
Total	$	210	$	194	$	—	$	86	$	490

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	73	$	31	$	—	$	—	$	104
International equity(*)	54		45		—		—		99
Fixed income:
U.S. Treasury, government, and agency bonds	—		21		—		—		21
Mortgage- and asset-backed securities	—		9		—		—		9
Corporate bonds	—		51		—		—		51
Pooled funds	—		23		—		—		23
Cash equivalents and other	—		7		—		—		7
Real estate investments	14		—		—		55		69
Private equity	—		—		—		29		29
Total	$	141	$	187	$	—	$	84	$	412

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

The fair values of other postretirement benefit plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	3	$	2	$	—	$	—	$	5
International equity(*)	2		2		—		—		4
Fixed income:
U.S. Treasury, government, and agency bonds	—		1		—		—		1
Corporate bonds	—		2		—		—		2
Pooled funds	—		1		—		—		1
Cash equivalents and other	2		—		—		—		2
Real estate investments	1		—		—		2		3
Private equity	—		—		—		1		1
Total	$	8	$	8	$	—	$	3	$	19

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	3	$	1	$	—	$	—	$	4
International equity(*)	2		2		—		—		4
Fixed income:
U.S. Treasury, government, and agency bonds	—		1		—		—		1
Corporate bonds	—		2		—		—		2
Pooled funds	—		1		—		—		1
Cash equivalents and other	1		—		—		—		1
Real estate investments	1		—		—		2		3
Private equity	—		—		—		1		1
Total	$	7	$	7	$	—	$	3	$	17

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

Employee Savings Plan

The Company also sponsors a 401(k) defined contribution plan covering substantially all employees. The Company provides an 85% matching contribution on up to 6% of an employee's base salary. Total matching contributions made to the plan for 2016, 2015, and 2014 were $5 million, $4 million, and $4 million, respectively.

Mississippi Power [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

The Company has a defined benefit, trusteed, pension plan covering substantially all employees. This qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). On December 19, 2016, the Company voluntarily contributed $47 million to the qualified pension plan. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2017. The Company also provides certain defined benefit pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, the Company provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The Company funds its other postretirement trusts to the extent required by the FERC. For the year ending December 31, 2017, no other postretirement trust contributions are expected.

Actuarial Assumptions

The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below.

Assumptions used to determine net periodic costs:	2016		2015		2014
Pension plans
Discount rate – benefit obligations	4.69	%	4.17	%	5.01	%
Discount rate – interest costs	3.97		4.17		5.01
Discount rate – service costs	5.04		4.49		5.01
Expected long-term return on plan assets	8.20		8.20		8.20
Annual salary increase	4.46		3.59		3.59
Other postretirement benefit plans
Discount rate – benefit obligations	4.47	%	4.03	%	4.85	%
Discount rate – interest costs	3.66		4.03		4.85
Discount rate – service costs	4.88		4.38		4.85
Expected long-term return on plan assets	7.07		7.23		7.30
Annual salary increase	4.46		3.59		3.59

Assumptions used to determine benefit obligations:	2016		2015
Pension plans
Discount rate	4.44	%	4.69	%
Annual salary increase	4.46		4.46
Other postretirement benefit plans
Discount rate	4.22	%	4.47	%
Annual salary increase	4.46		4.46

The Company estimates the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of seven different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio.

An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO as of December 31, 2016 were as follows:

	Initial Cost Trend Rate		Ultimate Cost Trend Rate		Year That Ultimate Rate is Reached
Pre-65	6.50	%	4.50	%	2025
Post-65 medical	5.00		4.50		2025
Post-65 prescription	10.00		4.50		2025

An annual increase or decrease in the assumed medical care cost trend rate of 1% would affect the APBO and the service and interest cost components at December 31, 2016 as follows:

	1 Percent Increase		1 Percent Decrease
	(in millions)
Benefit obligation	$	5	$	4
Service and interest costs	—		—

Pension Plans

The total accumulated benefit obligation for the pension plans was $479 million at December 31, 2016 and $447 million at December 31, 2015. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	500		$	513
Service cost	13			13
Interest cost	19			21
Benefits paid	(20		)	(22		)
Actuarial (gain) loss	22			(25		)
Balance at end of year	534			500
Change in plan assets
Fair value of plan assets at beginning of year	430			446
Actual return (loss) on plan assets	39			4
Employer contributions	50			2
Benefits paid	(20		)	(22		)
Fair value of plan assets at end of year	499			430
Accrued liability	$	(35	)	$	(70	)

At December 31, 2016, the projected benefit obligations for the qualified and non-qualified pension plans were $504 million and $30 million, respectively. All pension plan assets are related to the qualified pension plan.

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's pension plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	154		$	144
Other current liabilities	(3		)	(3		)
Employee benefit obligations	(32		)	(67		)

Presented below are the amounts included in regulatory assets at December 31, 2016 and 2015 related to the defined benefit pension plans that had not yet been recognized in net periodic pension cost along with the estimated amortization of such amounts for 2017.

	2016		2015		Estimated Amortization in 2017
	(in millions)
Prior service cost	$	3	$	2	$	1
Net (gain) loss	151		142		7
Regulatory assets	$	154	$	144

The changes in the balance of regulatory assets related to the defined benefit pension plans for the years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Regulatory assets:
Beginning balance	$	144		$	151
Net (gain) loss	16			4
Change in prior service costs	2			—
Reclassification adjustments:
Amortization of prior service costs	(1		)	(1		)
Amortization of net gain (loss)	(7		)	(10		)
Total reclassification adjustments	(8		)	(11		)
Total change	10			(7		)
Ending balance	$	154		$	144

Components of net periodic pension cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	13		$	13		$	10
Interest cost	19			21			20
Expected return on plan assets	(35		)	(33		)	(29		)
Recognized net (gain) loss	7			10			5
Net amortization	1			1			1
Net periodic pension cost	$	5		$	12		$	7

Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Company has elected to amortize changes in the market value of all plan assets over five years rather than recognize the changes immediately. As a result, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets.

Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	22
2018	23
2019	24
2020	26
2021	27
2022 to 2026	154

Other Postretirement Benefits

Changes in the APBO and in the fair value of plan assets during the plan years ended December 31, 2016 and 2015 were as follows:

	2016			2015
	(in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	97		$	96
Service cost	1			1
Interest cost	3			4
Benefits paid	(6		)	(5		)
Actuarial (gain) loss	1			(1		)
Plan amendment	—			1
Retiree drug subsidy	1			1
Balance at end of year	97			97
Change in plan assets
Fair value of plan assets at beginning of year	23			24
Actual return (loss) on plan assets	1			—
Employer contributions	4			3
Benefits paid	(5		)	(4		)
Fair value of plan assets at end of year	23			23
Accrued liability	$	(74	)	$	(74	)

Amounts recognized in the balance sheets at December 31, 2016 and 2015 related to the Company's other postretirement benefit plans consist of the following:

	2016			2015
	(in millions)
Other regulatory assets, deferred	$	21		$	21
Other regulatory liabilities, deferred	(2		)	(3		)
Employee benefit obligations	(74		)	(74		)

Approximately $19 million and $18 million was included in net regulatory assets at December 31, 2016 and 2015, respectively, related to the net loss for the other postretirement benefit plans that had not yet been recognized in net periodic other postretirement benefit cost. The estimated amortization of such amounts for 2017 is $1 million.

The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2016 and 2015 are presented in the following table:

	2016			2015
	(in millions)
Net regulatory assets (liabilities):
Beginning balance	$	18		$	16
Net (gain) loss	2			—
Change in prior service costs	—			3
Reclassification adjustments:
Amortization of net gain (loss)	(1		)	(1		)
Total reclassification adjustments	(1		)	(1		)
Total change	1			2
Ending balance	$	19		$	18

Components of the other postretirement benefit plans' net periodic cost were as follows:

	2016			2015			2014
	(in millions)
Service cost	$	1		$	1		$	1
Interest cost	3			4			4
Expected return on plan assets	(1		)	(2		)	(2		)
Net amortization	1			1			—
Net periodic postretirement benefit cost	$	4		$	4		$	3

Future benefit payments, including prescription drug benefits, reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Estimated benefit payments are reduced by drug subsidy receipts expected as a result of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 as follows:

	Benefit Payments		Subsidy Receipts			Total
	(in millions)
2017	$	6	$	(1	)	$	5
2018	6		(1		)	5
2019	7		(1		)	6
2020	7		(1		)	6
2021	7		(1		)	6
2022 to 2026	36		(1		)	35

Benefit Plan Assets

Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code of 1986, as amended (Internal Revenue Code). The Company's investment policies for both the pension plan and the other postretirement benefit plans cover a diversified mix of assets, including equity and fixed income securities, real estate, and private equity. Derivative instruments are used primarily to gain efficient exposure to the various asset classes and as hedging tools. The Company minimizes the risk of large losses primarily through diversification but also monitors and manages other aspects of risk.

The composition of the Company's pension plan and other postretirement benefit plan assets as of December 31, 2016 and 2015, along with the targeted mix of assets for each plan, is presented below:

	Target		2016		2015
Pension plan assets:
Domestic equity	26	%	29	%	30	%
International equity	25		22		23
Fixed income	23		29		23
Special situations	3		2		2
Real estate investments	14		13		16
Private equity	9		5		6
Total	100	%	100	%	100	%
Other postretirement benefit plan assets:
Domestic equity	21	%	23	%	24	%
International equity	20		18		18
Domestic fixed income	38		43		38
Special situations	3		2		2
Real estate investments	11		10		13
Private equity	7		4		5
Total	100	%	100	%	100	%

The investment strategy for plan assets related to the Company's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Company employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices.

Investment Strategies

Detailed below is a description of the investment strategies for each major asset category for the pension and other postretirement benefit plans disclosed above:

• Domestic equity. A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

• International equity. A mix of growth stocks and value stocks with both developed and emerging market exposure, managed both actively and through passive index approaches.

• Fixed income. A mix of domestic and international bonds.

• Special situations. Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies as well as investments in promising new strategies of a longer-term nature.

• Real estate investments. Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities.

• Private equity. Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

Benefit Plan Asset Fair Values

Following are the fair value measurements for the pension plan and the other postretirement benefit plan assets as of December 31, 2016 and 2015. The fair values presented are prepared in accordance with GAAP. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

Valuation methods of the primary fair value measurements disclosed in the following tables are as follows:

• Domestic and international equity.Investments in equity securities such as common stocks, American depositary receipts, and real estate investment trusts that trade on a public exchange are classified as Level 1 investments and are valued at the closing price in the active market. Equity investments with unpublished prices (i.e. pooled funds) are valued as Level 2, when the underlying holdings used to value the investment are comprised of Level 1 or Level 2 equity securities.

• Fixed income.Investments in fixed income securities are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.

• Real estate investments, private equity, and special situations investments.Investments in real estate, private equity, and special situations are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.

The fair values of pension plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2015, investments in special situations were presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	95	$	44	$	—	$	—	$	139
International equity(*)	58		51		—		—		109
Fixed income:
U.S. Treasury, government, and agency bonds	—		28		—		—		28
Mortgage- and asset-backed securities	—		1		—		—		1
Corporate bonds	—		46		—		—		46
Pooled funds	—		25		—		—		25
Cash equivalents and other	47		—		—		—		47
Real estate investments	15		—		—		54		69
Special situations	—		—		—		8		8
Private equity	—		—		—		26		26
Total	$	215	$	195	$	—	$	88	$	498

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	76	$	32	$	—	$	—	$	108
International equity(*)	55		46		—		—		101
Fixed income:
U.S. Treasury, government, and agency bonds	—		21		—		—		21
Mortgage- and asset-backed securities	—		9		—		—		9
Corporate bonds	—		53		—		—		53
Pooled funds	—		23		—		—		23
Cash equivalents and other	—		7		—		—		7
Real estate investments	14		—		—		57		71
Private equity	—		—		—		30		30
Total	$	145	$	191	$	—	$	87	$	423

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

The fair values of other postretirement benefit plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2016:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	4	$	2	$	—	$	—	$	6
International equity(*)	2		2		—		—		4
Fixed income:
U.S. Treasury, government, and agency bonds	—		5		—		—		5
Mortgage- and asset-backed securities	—		—		—		—		—
Corporate bonds	—		2		—		—		2
Pooled funds	—		1		—		—		1
Cash equivalents and other	2		—		—		—		2
Real estate investments	1		—		—		2		3
Private equity	—		—		—		1		1
Total	$	9	$	12	$	—	$	3	$	24

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	3	$	1	$	—	$	—	$	4
International equity(*)	2		2		—		—		4
Fixed income:
U.S. Treasury, government, and agency bonds	—		6		—		—		6
Mortgage- and asset-backed securities	—		—		—		—		—
Corporate bonds	—		2		—		—		2
Pooled funds	—		1		—		—		1
Cash equivalents and other	1		—		—		—		1
Real estate investments	1		—		—		3		4
Private equity	—		—		—		1		1
Total	$	7	$	12	$	—	$	4	$	23

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

Employee Savings Plan

The Company also sponsors a 401(k) defined contribution plan covering substantially all employees. The Company provides an 85% matching contribution on up to 6% of an employee's base salary. Total matching contributions made to the plan for 2016, 2015, and 2014 were $5 million each year.

Southern Company Gas [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

Effective July 1, 2016, in connection with the Merger, SCS became the sponsor of the Company's pension and other post-retirement benefit plans.

The Company has a qualified defined benefit, trusteed, pension plan – AGL Resources Inc. Retirement Plan – covering certain eligible employees, which was closed in 2012 to new employees. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). On September 12, 2016, the Company voluntarily contributed $125 million to the qualified pension plan. No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2017. The Company also provides certain non-qualified defined benefit and defined contribution pension plans for a selected group of management and highly compensated employees. Benefits under these non-qualified pension plans are funded on a cash basis. In addition, the Company provides certain medical care and life insurance benefits for eligible retired employees through a postretirement benefit plan – AGL Welfare Plan. The Company also has a separate unfunded supplemental retirement health care plan that provides medical care and life insurance benefits to employees of discontinued businesses. For the year ending December 31, 2017, no other postretirement trust contributions are expected.

In connection with the Merger, the Company performed updated valuations of its pension and other postretirement benefit plan assets and obligations to reflect actual census data at the new measurement date of July 1, 2016. This valuation resulted in increases to the projected benefit obligations for the pension and other postretirement benefit plans of approximately $177 million and $20 million, respectively, a decrease in the fair value of pension plan assets of $10 million, and an increase in the fair value of other postretirement benefit plan assets of $1 million. The Company also recorded a related regulatory asset of $437 million related to unrecognized prior service cost and actuarial gain/loss, as it is probable that this amount will be recovered through future rates for the natural gas distribution utilities. The previously unrecognized prior service cost and actuarial gain/loss related to non-utility subsidiaries were eliminated through purchase accounting adjustments.

Actuarial Assumptions

The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the periods presented and the benefit obligations as of the measurement date are presented below.

	Successor		Predecessor
	July 1, 2016 through December 31,		January 1, 2016 through June 30,		Years Ended December 31,
Assumptions used to determine net periodic costs:	2016		2016		2015		2014
Pension plans
Discount rate – interest costs(a)	3.21	%	4.00	%	4.20	%	5.00	%
Discount rate – service costs(a)	4.07		4.80		4.20		5.00
Expected long-term return on plan assets	7.75		7.80		7.80		7.80
Annual salary increase	3.50		3.70		3.70		3.70
Pension band increase(b)	2.00		2.00		2.00		2.00
Other postretirement benefit plans
Discount rate – interest costs(a)	2.84	%	3.60	%	4.00	%	4.70	%
Discount rate – service costs(a)	3.96		4.70		4.00		4.70
Expected long-term return on plan assets	5.93		6.60		7.80		7.80
Annual salary increase	3.50		3.70		3.70		3.70

(a) Effective January 1, 2016, the Company uses a spot rate approach to estimate the service cost and interest cost components. Previously, the Company estimated these components using a single weighted average discount rate.

(b) Only applicable to Nicor Gas union employees. The pension bands for the former Nicor plan reflect the negotiated rates of 2.0% for each of 2016 and 2017, in accordance with a March 2014 union agreement.

	Successor		Predecessor
Assumptions used to determine benefit obligations:	December 31, 2016		December 31, 2015
Pension plans
Discount rate	4.39	%	4.6	%
Annual salary increase	3.50		3.7
Pension band increase(*)	2.00		2.0
Other postretirement benefit plans
Discount rate	4.15	%	4.4	%
Annual salary increase	3.50		3.7

(*) Only applicable to Nicor Gas union employees. The pension bands for the former Nicor plan reflect the negotiated rates of 2.0% for each of 2016 and 2017, in accordance with a March 2014 union agreement.

The Company estimates the expected return on plans assets by evaluating expected bond returns, equity risk premiums, asset allocations, the effects of active plan management, the impact of periodic plan asset rebalancing, and historical performance. The Company also considers guidance from its investment advisors in making a final determination of its expected rate of return on assets. To the extent the actual rate of return on assets realized over the course of a year is greater or less than the assumed rate, it does not affect that year's annual pension or welfare plan cost; rather, this gain or loss reduces or increases future pension or welfare plan costs.

An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO as of December 31, 2016 were as follows:

	Initial Cost Trend Rate		Ultimate Cost Trend Rate		Year That Ultimate Rate is Reached
Pre-65	6.60	%	4.50	%	2038
Post-65 medical	8.40		4.50		2038
Post-65 prescription	8.40		4.50		2038

An annual increase or decrease in the assumed medical care cost trend rate of 1% would affect the APBO and the service and interest cost components as follows:

	1 Percent Increase		1 Percent Decrease
	(in millions)
Successor – December 31, 2016
Benefit obligation	$	14	$	12
Service and interest costs	—		—

Pension Plans

The total accumulated benefit obligation for the pension plans was $1.1 billion at December 31, 2016 and $1.0 billion at December 31, 2015. Changes in the projected benefit obligations and the fair value of plan assets for the successor period ended December 31, 2016 and for the predecessor periods ended June 30, 2016 and December 31, 2015 were as follows:

	Successor			Predecessor
	July 1, 2016 through December 31, 2016			January 1, 2016 through June 30, 2016			2015
	(in millions)			(in millions)
Change in benefit obligation
Benefit obligation at beginning of period	$	1,244		$	1,067		$	1,098
Service cost	15			13			28
Interest cost	20			21			45
Benefits paid	(31		)	(26		)	(49		)
Actuarial loss (gain)	(115		)	169			(55		)
Balance at end of period	1,133			1,244			1,067
Change in plan assets
Fair value of plan assets at beginning of period	837			847			906
Actual return (loss) on plan assets	48			15			(12		)
Employer contributions	129			1			2
Benefits paid	(31		)	(26		)	(49		)
Fair value of plan assets at end of period	983			837			847
Accrued liability	$	150		$	407		$	220

At December 31, 2016, the projected benefit obligations for the qualified and non-qualified pension plans were $1.1 billion and $39 million, respectively. All pension plan assets are related to the qualified pension plan.

Amounts recognized in the consolidated balance sheets at December 31, 2016 and 2015 related to the Company's pension plans consist of the following:

	Successor			Predecessor
	2016			2015
	(in millions)			(in millions)
Other regulatory assets, deferred	$	267		$	88
Other deferred charges and assets	58			78
Other current liabilities	(2		)	(4		)
Employee benefit obligations	(206		)	(294		)

Presented below are the amounts included in accumulated OCI and regulatory assets at December 31, 2016 and 2015 related to the defined benefit pension plans that had not yet been recognized in net periodic pension cost along with the estimated amortization of such amounts for 2017.

	Prior Service Cost			Net (Gain) Loss
	(in millions)
Successor – Balance at December 31, 2016:
Accumulated OCI	$	—		$	(43	)
Regulatory assets (liabilities)	(2		)	269
Total	$	(2	)	$	226
Predecessor – Balance at December 31, 2015:
Accumulated OCI	$	(4	)	$	286
Regulatory assets	—			88
Total	$	(4	)	$	374
Estimated amortization in net periodic cost in 2017:
Regulatory assets (liabilities)	$	1		$	(21	)

The components of OCI and the changes in the balance of regulatory assets related to the defined benefit pension plans for the successor period ended December 31, 2016 and for the predecessor periods ended June 30, 2016 and December 31, 2015 are presented in the following table:

	Accumulated OCI			Regulatory Assets
	(in millions)
Predecessor – Balance at December 31, 2014:	$	301		$	76
Net (gain) loss	—			22
Reclassification adjustments:
Amortization of prior service costs	2			—
Amortization of net loss	(21		)	(10		)
Total reclassification adjustments	(19		)	(10		)
Total change	(19		)	12
Predecessor – Balance at December 31, 2015:	$	282		$	88
Reclassification adjustments:
Amortization of prior service costs	1			—
Amortization of net loss	(9		)	(4		)
Total reclassification adjustments	(8		)	(4		)
Total change	(8		)	(4		)
Predecessor – Balance at June 30, 2016:	$	274		$	84
Successor – Balance at July 1, 2016:	$	—		$	368
Net (gain) loss	(43		)	(87		)
Reclassification adjustments:
Amortization of prior service costs	—			1
Amortization of net loss	—			(15		)
Total reclassification adjustments	—			(14		)
Total change	(43		)	(101		)
Successor – Balance at December 31, 2016:	$	(43	)	$	267

Components of net periodic pension costs for the periods presented were as follows:

	Successor			Predecessor
	July 1, 2016 through December 31,			January 1, 2016 through June 30,			Years Ended December 31,
	2016			2016			2015			2014
	(in millions)			(in millions)
Service cost	$	15		$	13		$	28		$	24
Interest cost	20			21			45			47
Expected return on plan assets	(35		)	(33		)	(65		)	(65		)
Amortization of regulatory assets	13			—			—			—
Amortization:
Prior service costs	—			(1		)	(2		)	(2		)
Net (gain)/loss	—			13			31			22
Net periodic pension cost	$	13		$	13		$	37		$	26

Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets.

Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	71
2018	72
2019	73
2020	74
2021	74
2022 to 2026	363

Other Postretirement Benefits

Changes in the APBO and the fair value of plan assets for the successor period ended December 31, 2016 and for the predecessor periods ended June 30, 2016 and December 31, 2015 were as follows:

	Successor			Predecessor
	July 1, 2016 through December 31, 2016			January 1, 2016 through June 30, 2016			2015
	(in millions)			(in millions)
Change in benefit obligation
Benefit obligation at beginning of period	$	338		$	318		$	334
Service cost	1			1			2
Interest cost	5			5			13
Benefits paid	(11		)	(11		)	(20		)
Actuarial loss (gain)	(26		)	24			(13		)
Retiree drug subsidy	—			—			1
Employee contributions	1			1			1
Balance at end of period	308			338			318
Change in plan assets
Fair value of plan assets at beginning of period	100			99			99
Actual return (loss) on plan assets	4			1			1
Employee contributions	1			1			1
Employer contributions	11			10			17
Benefits paid	(11		)	(11		)	(20		)
Retiree drug subsidy	—			—			1
Fair value of plan assets at end of year	105			100			99
Accrued liability	$	203		$	238		$	219

Amounts recognized in the consolidated balance sheets at December 31, 2016 and 2015 related to the Company's other postretirement benefit plans consist of the following:

	Successor			Predecessor
	2016			2015
	(in millions)			(in millions)
Other regulatory assets, deferred	$	52		$	30
Employee benefit obligations	(203		)	(219		)

Presented below are the amounts included in accumulated OCI and regulatory assets at December 31, 2016 and 2015 related to the other postretirement benefit plans that had not yet been recognized in net periodic other postretirement benefit cost. The estimated amortization of such amounts for 2017 is immaterial.

	Prior Service Cost			Net (Gain) Loss
	(in millions)
Successor – Balance at December 31, 2016:
Accumulated OCI	$	—		$	(3	)
Regulatory assets (liabilities)	(12		)	64
Total	$	(12	)	$	61
Predecessor – Balance at December 31, 2015:
Accumulated OCI	$	—		$	36
Regulatory assets (liabilities)	(15		)	45
Total	$	(15	)	$	81

The components of OCI, along with the changes in the balance of regulatory assets (liabilities), related to the other postretirement benefit plans for the successor period ended December 31, 2016 and for the predecessor periods ended June 30, 2016 and December 31, 2015 are presented in the following table:

	Accumulated OCI			Regulatory Assets
	(in millions)
Predecessor – Balance at December 31, 2014:	$	36		$	39
Net (gain) loss	2			(8		)
Reclassification adjustments:
Amortization of prior service costs	—			2
Amortization of net loss	(2		)	(3		)
Total reclassification adjustments	(2		)	(1		)
Total change	—			(9		)
Predecessor – Balance at December 31, 2015:	$	36		$	30
Reclassification adjustments:
Amortization of prior service costs	—			1
Amortization of net loss	(1		)	(1		)
Total reclassification adjustments	(1		)	—
Total change	(1		)	—
Predecessor – Balance at June 30, 2016:	$	35		$	30
Successor – Balance at July 1, 2016:	$	—		$	77
Net (gain) loss	(3		)	(23		)
Reclassification adjustments:
Amortization of prior service costs	—			1
Amortization of net loss	—			(3		)
Total reclassification adjustments	—			(2		)
Total change	(3		)	(25		)
Successor – Balance at December 31, 2016:	$	(3	)	$	52

Components of the other postretirement benefit plans' net periodic cost for the periods presented were as follows:

	Successor			Predecessor
	July 1, 2016 through December 31,			January 1, 2016 through June 30,			Years Ended December 31,
	2016			2016			2015			2014
	(in millions)			(in millions)
Service cost	$	1		$	1		$	2		$	2
Interest cost	5			5			13			15
Expected return on plan assets	(3		)	(3		)	(7		)	(7		)
Amortization of regulatory assets	2			—			—			—
Amortization:
Prior service costs	—			(1		)	(3		)	(3		)
Net (gain)/loss	—			2			6			6
Net periodic postretirement benefit cost	$	5		$	4		$	11		$	13

Future benefit payments, including prescription drug benefits, reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. At December 31, 2016, estimated benefit payments were as follows:

	Benefit Payments
	(in millions)
2017	$	20
2018	20
2019	21
2020	22
2021	22
2022 to 2026	111

Benefit Plan Assets

Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code of 1986, as amended. The Company's investment policies for both the pension plan and the other postretirement benefit plans cover a diversified mix of assets, including equity and fixed income securities, real estate, and private equity. The Company minimizes the risk of large losses primarily through diversification but also monitors and manages other aspects of risk.

The assets of the AGL Resources Inc. Retirement Plan (AGL plan) were allocated 69% equity, 20% fixed income, 1% cash, and 10% other at December 31, 2016 compared to the Company's targets of 53% equity, 15% fixed income, 2% cash, and 30% other. The investment policy provides for variation around the target asset allocation in the form of ranges.

The assets of the Company's other postretirement benefit plan were allocated 74% equity, 23% fixed income, 1% cash, and 2% other at December 31, 2016 compared to the Company's targets of 72% equity, 24% fixed income, 1% cash, and 3% other. The investment policy provides for variation around the target asset allocation in the form of ranges.

The assets of the AGL plan and the Company's other postretirement benefit plan were each allocated 72% equity and 28% fixed income at December 31, 2015 compared to the Company's targets of 70% to 95% equity, 5% to 20% fixed income, and up to 10% cash. The investment policies provided for some variation in these targets in the form of ranges around the target.

The investment strategy for plan assets related to the Company's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Company employs a formal rebalancing program for its pension plan assets. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices.

Investment Strategies

Detailed below is a description of the investment strategies for the successor period for each major asset category for the pension and other postretirement benefit plans disclosed above:

• Domestic equity. A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches.

• International equity. A mix of growth stocks and value stocks with both developed and emerging market exposure, managed both actively and through passive index approaches.

• Fixed income. A mix of domestic and international bonds.

• Special situations. Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies as well as investments in promising new strategies of a longer-term nature.

• Real estate investments. Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities.

• Private equity. Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt.

The investment strategies for the predecessor periods followed a policy to preserve the plans' capital and maximize investment earnings in excess of inflation within acceptable levels of capital market volatility. To accomplish this goal, the plans' assets were managed to optimize long-term return while maintaining a high standard of portfolio quality and diversification. In developing the allocation policy for the assets of the pension and other postretirement benefit plans, the Company examined projections of asset returns and volatility over a long-term horizon. In connection with this analysis, the risk and return trade-offs of alternative asset classes and asset mixes were evaluated given long-term historical relationships as well as prospective capital market returns. The Company also conducted asset-liability studies to match projected asset growth with projected liability growth to determine whether there is sufficient liquidity for projected benefit payments. Asset mix guidelines were developed by incorporating the results of these analyses with an assessment of the Company's risk posture, and taking into account industry practices. The Company periodically evaluated its investment strategy to ensure that plan assets were sufficient to meet the benefit obligations of the plans. As part of the ongoing evaluation, the Company made changes to its targeted asset allocations and investment strategy.

Benefit Plan Asset Fair Values

Following are the fair value measurements for the pension plan and the other postretirement benefit plan assets as of December 31, 2016 and 2015. The fair values presented are prepared in accordance with GAAP. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation for the successor period, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

Valuation methods of the primary fair value measurements disclosed in the 2016 tables are as follows:

• Domestic and international equity.Investments in equity securities such as common stocks, American depositary receipts, and real estate investment trusts that trade on a public exchange are classified as Level 1 investments and are valued at the closing price in the active market. Equity investments with unpublished prices (i.e. pooled funds) are valued as Level 2, when the underlying holdings used to value the investment are comprised of Level 1 or Level 2 equity securities.

• Fixed income.Investments in fixed income securities are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument.

• Real estate investments, private equity, and special situations investments.Investments in real estate, private equity, and special situations are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.

For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation for the predecessor periods, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate.

The fair values of pension plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2016, special situations (absolute return and hedge funds) investment assets are presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
Successor – As of December 31, 2016	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	142	$	343	$	—	$	—	$	485
International equity(*)	—		185		—		—		185
Fixed income:
U.S. Treasury, government, and agency bonds	—		85		—		—		85
Corporate bonds	—		41		—		—		41
Pooled funds	—		66		—		—		66
Cash equivalents and other	12		5		—		83		100
Real estate investments	4		—		—		15		19
Private equity	—		—		—		2		2
Total	$	158	$	725	$	—	$	100	$	983

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Predecessor – As of December 31, 2015
	Pension plans (a)
In millions	Level 1			Level 2			Level 3			Total			% of total
Cash	$	4		$	—		$	—		$	4		—	%
Equity securities:
U.S. large cap(b)	$	75		$	199		$	—		$	274		32	%
U.S. small cap(b)	57			24			—			81			9	%
International companies(c)	—			125			—			125			15	%
Emerging markets(d)	—			28			—			28			3	%
Total equity securities	$	132		$	376		$	—		$	508		59	%
Fixed income securities:
Corporate bonds(e)	$	—		$	91		$	—		$	91		11	%
Other (or gov't/muni bonds)	—			151			—			151			18	%
Total fixed income securities	$	—		$	242		$	—		$	242		29	%
Other types of investments:
Global hedged equity(f)	$	—		$	—		$	40		$	40		5	%
Absolute return(g)	—			—			42			42			5	%
Private capital(h)	—			—			20			20			2	%
Total other investments	$	—		$	—		$	102		$	102		12	%
Total assets at fair value	$	136		$	618		$	102		$	856		100	%
% of fair value hierarchy	16		%	72		%	12		%	100		%

(a) Includes $9 million at December 31, 2015 of medical benefit (health and welfare) component for 401(h) accounts to fund a portion of the other retirement benefits.

(b) Includes funds that invest primarily in U.S. common stocks.

(c) Includes funds that invest primarily in foreign equity and equity-related securities.

(d) Includes funds that invest primarily in common stocks of emerging markets.

(e) Includes funds that invest primarily in investment grade debt and fixed income securities.

(f) Includes funds that invest in limited/general partnerships, managed accounts, and other investment entities issued by non-traditional firms or "hedge funds."

(g) Includes funds that invest primarily in investment vehicles and commodity pools as a "fund of funds."

(h) Includes funds that invest in private equity and small buyout funds, partnership investments, direct investments, secondary investments, directly/indirectly in real estate and may invest in equity securities of real estate related companies, real estate mortgage loans, and real estate mezzanine loans.

The fair values of other postretirement benefit plan assets as of December 31, 2016 and 2015 are presented below. These fair value measurements exclude cash, receivables related to investment income, pending investments sales, and payables related to pending investment purchases. For 2016, special situations (absolute return and hedge funds) investment assets are presented in the table below based on the nature of the investment.

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
Successor – As of December 31, 2016	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Domestic equity(*)	$	3	$	58	$	—	$	—	$	61
International equity(*)	—		18		—		—		18
Fixed income:
Pooled funds	—		23		—		—		23
Cash equivalents and other	1		—		—		2		3
Total	$	4	$	99	$	—	$	2	$	105

(*) Level 1 securities consist of actively traded stocks while Level 2 securities consist of pooled funds. Management believes that the portfolio is well-diversified with no significant concentrations of risk.

	Predecessor – As of December 31, 2015
	Welfare plans
In millions	Level 1			Level 2			Level 3			Total			% of total
Cash	$	1		$	—		$	—		$	1		1	%
Equity securities:
U.S. large cap(a)	$	—		$	52		$	—		$	52		58	%
U.S. small cap(a)	—			—			—			—			—	%
International companies(b)	—			15			—			15			17	%
Emerging markets(c)	—			—			—			—			—	%
Total equity securities	$	—		$	67		$	—		$	67		75	%
Fixed income securities:
Corporate bonds(d)	$	—		$	22		$	—		$	22		24	%
Other (or gov't/muni bonds)	—			—			—			—			—	%
Total fixed income securities	$	—		$	22		$	—		$	22		24	%
Other types of investments:
Global hedged equity(e)	$	—		$	—		$	—		$	—		—	%
Absolute return(f)	—			—			—			—			—	%
Private capital(g)	—			—			—			—			—	%
Total other investments	$	—		$	—		$	—		$	—		—	%
Total assets at fair value	$	1		$	89		$	—		$	90		100	%
% of fair value hierarchy	1		%	99		%	—		%	100		%

(a) Includes funds that invest primarily in U.S. common stocks.

(b) Includes funds that invest primarily in foreign equity and equity-related securities.

(c) Includes funds that invest primarily in common stocks of emerging markets.

(d) Includes funds that invest primarily in investment grade debt and fixed income securities.

(e) Includes funds that invest in limited/general partnerships, managed accounts, and other investment entities issued by non-traditional firms or "hedge funds."

(f) Includes funds that invest primarily in investment vehicles and commodity pools as a "fund of funds."

(g) Includes funds that invest in private equity and small buyout funds, partnership investments, direct investments, secondary investments, directly/indirectly in real estate and may invest in equity securities of real estate related companies, real estate mortgage loans, and real estate mezzanine loans.

Employee Savings Plan

SCS sponsors 401(k) defined contribution plans covering certain eligible Southern Company Gas employees. The AGL Resources Inc. 401(k) plans provide matching contributions of either 65% on up to 8% of an employee's eligible compensation, or a 100% matching contribution on up to 3% of an employee's eligible compensation, followed by a 75% matching contribution on up to the next 3% of an employee's eligible compensation. Total matching contributions made to the AGL Resources Inc. 401(k) plans for the successor period ended December 31, 2016 were $8 million and for the predecessor periods ended June 30, 2016 and December 31, 2015 and 2014 were $10 million, $16 million, and $14 million, respectively.

For employees not accruing a benefit under the AGL Resources Inc. Retirement Plan, additional contributions made to the 401(k) plans for the successor period ended December 31, 2016 were not material and for the predecessor periods ended June 30, 2016 and December 31, 2015 and 2014 were $2 million, $2 million, and $1 million, respectively.