Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2016

Compensation and Retirement Disclosure [Abstract]

Summary of Changes in Projected Benefit Obligation, Plan Assets, Funded Status, Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss)

The following table summarizes the changes in benefit obligations and plan assets for the years ended December 31, and the funded status and amounts recognized in the Consolidated Balance Sheet at December 31 for the retirement plans:

	Pension Plans						Postretirement Welfare Plan
(Dollars in Millions)	2016			2015			2016			2015
Change In Projected Benefit Obligation
Benefit obligation at beginning of measurement period	$	4,650		$	4,612		$	93		$	104
Service cost		177			188			–			–
Interest cost		211			195			3			3
Participants’ contributions		–			–			10			10
Actuarial loss (gain)		234			(176	)		(14	)		(5	)
Lump sum settlements		(61	)		(37	)		–			–
Benefit payments		(138	)		(132	)		(19	)		(21	)
Federal subsidy on benefits paid		–			–			2			2
Benefit obligation at end of measurement period(a)	$	5,073		$	4,650		$	75		$	93
Change In Fair Value Of Plan Assets
Fair value at beginning of measurement period	$	3,355		$	3,187		$	82		$	85
Actual return on plan assets		230			(99	)		2			–
Employer contributions		383			436			7			8
Participants’ contributions		–			–			10			10
Lump sum settlements		(61	)		(37	)		–			–
Benefit payments		(138	)		(132	)		(19	)		(21	)
Fair value at end of measurement period	$	3,769		$	3,355		$	82		$	82
Funded (Unfunded) Status	$	(1,304	)	$	(1,295	)	$	7		$	(11	)
Components Of The Consolidated Balance Sheet
Noncurrent benefit asset	$	–		$	–		$	7		$	–
Current benefit liability		(22	)		(21	)		–			–
Noncurrent benefit liability		(1,282	)		(1,274	)		–			(11	)
Recognized amount	$	(1,304	)	$	(1,295	)	$	7		$	(11	)
Accumulated Other Comprehensive Income (Loss), Pretax
Net actuarial gain (loss)	$	(1,901	)	$	(1,806	)	$	66		$	55
Net prior service credit (cost)		2			7			25			28
Recognized amount	$	(1,899	)	$	(1,799	)	$	91		$	83

(a) At December 31, 2016 and 2015, the accumulated benefit obligation for all pension plans was $4.6 billion and $4.3 billion.

Pension Plans with Benefit Obligations in Excess of Plan Assets

The following table provides information for pension plans with benefit obligations in excess of plan assets at December 31:

(Dollars in Millions)	2016		2015
Pension Plans with Projected Benefit Obligations in Excess of Plan Assets
Projected benefit obligation	$	5,073	$	4,650
Fair value of plan assets		3,769		3,355
Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets
Projected benefit obligation	$	5,073	$	4,650
Accumulated benefit obligation		4,625		4,310
Fair value of plan assets		3,769		3,355

Components of Net Periodic Benefit Cost and Other Amounts Recognized in Accumulated Other Comprehensive Income (Loss)

The following table sets forth the components of net periodic benefit cost and other amounts recognized in accumulated other comprehensive income (loss) for the years ended December 31 for the retirement plans:

	Pension Plans									Postretirement Welfare Plan
(Dollars in Millions)	2016			2015			2014			2016			2015			2014
Components Of Net Periodic Benefit Cost
Service cost	$	177		$	188		$	152		$	–		$	–		$	–
Interest cost		211			195			197			3			3			3
Expected return on plan assets		(266	)		(223	)		(208	)		(1	)		(1	)		(1	)
Prior service cost (credit) and transition obligation (asset) amortization		(5	)		(4	)		(5	)		(3	)		(3	)		(3	)
Actuarial loss (gain) amortization		175			234			158			(4	)		(4	)		(6	)
Net periodic benefit cost	$	292		$	390		$	294		$	(5	)	$	(5	)	$	(7	)
Other Changes In Plan Assets And Benefit Obligations
Recognized In Other Comprehensive Income (Loss)
Net actuarial gain (loss) arising during the year	$	(270	)	$	(146	)	$	(719	)	$	15		$	4		$	(14	)
Net actuarial loss (gain) amortized during the year		175			234			158			(4	)		(4	)		(6	)
Net prior service cost (credit) and transition obligation (asset) amortized during the year		(5	)		(4	)		(5	)		(3	)		(3	)		(3	)
Total recognized in other comprehensive income (loss)	$	(100	)	$	84		$	(566	)	$	8		$	(3	)	$	(23	)
Total recognized in net periodic benefit cost and other comprehensive income (loss)(a)(b)	$	(392	)	$	(306	)	$	(860	)	$	13		$	2		$	(16	)

(a) The pretax estimated actuarial loss (gain) and prior service cost (credit) for the pension plans that will be amortized from accumulated other comprehensive income (loss) into net periodic benefit cost in 2017 are $127 million and $(2) million, respectively.

(b) The pretax estimated actuarial loss (gain) and prior service cost (credit) for the postretirement welfare plan that will be amortized from accumulated other comprehensive income (loss) into net periodic benefit cost in 2017 are $(6) million and $(3) million, respectively.

Weighted Average Assumptions to Determine Projected Benefit Obligations

The following table sets forth weighted average assumptions used to determine the projected benefit obligations at December 31:

	Pension Plans						Postretirement Welfare Plan
(Dollars in Millions)	2016			2015			2016			2015
Discount rate(a)		4.27	%		4.45	%		3.57	%		3.59	%
Rate of compensation increase(b)		3.58			4.06			*			*
Health care cost trend rate for the next year(c)								7.00	%		6.50	%
Effect on accumulated postretirement benefit obligation
One percent increase							$	4		$	5
One percent decrease								(4	)		(5	)

(a) The discount rates were developed using a cash flow matching bond model with a modified duration for the qualified pension plan, non-qualified pension plan and postretirement welfare plan of 15.5, 12.1, and 6.2 years, respectively, for 2016, and 15.0, 11.9 and 6.3 years, respectively, for 2015.

(b) Determined on an active liability-weighted basis.

(c) The 2016 and 2015 rates are assumed to decrease gradually to 5.00 percent by 2025 and 2019, respectively, and remain at this level thereafter.

* Not applicable

Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost

The following table sets forth weighted average assumptions used to determine net periodic benefit cost for the years ended December 31:

	Pension Plans									Postretirement Welfare Plan
(Dollars in Millions)	2016			2015			2014			2016			2015			2014
Discount rate (a)		4.45	%		4.13	%		4.97	%		3.59	%		3.46	%		3.93	%
Expected return on plan assets (b)		7.50			7.50			7.50			1.50			1.50			1.50
Rate of compensation increase(c)		4.06			4.07			4.02			*			*			*
Health care cost trend rate(d)
Prior to age 65											6.50	%		7.00	%		7.50	%
After age 65											6.50			7.00			7.50
Effect on total of service cost and interest cost
One percent increase										$	–		$	–		$	–
One percent decrease											–			–			–

(a) The discount rates were developed using a cash flow matching bond model with a modified duration for the qualified pension plan, non-qualified pension plan and postretirement welfare plan of 15.0, 11.9, and 6.3 years, respectively, for 2016, and 15.9, 12.4 and 6.8 years, respectively, for 2015.

(b) With the help of an independent pension consultant, the Company considers several sources when developing its expected long-term rates of return on plan assets assumptions, including, but not limited to, past returns and estimates of future returns given the plans’ asset allocation, economic conditions, and peer group LTROR information. The Company determines its expected long-term rates of return reflecting current economic conditions and plan assets.

(c) Determined on an active liability weighted basis.

(d) The pre-65 and post-65 rates are both assumed to decrease gradually to 5.00 percent by 2019 and remain at that level thereafter.

* Not applicable

Summary of Plan Investment Assets Measured at Fair Value

The following table summarizes plan investment assets measured at fair value at December 31:

	Qualified Pension Plan																Postretirement Welfare Plan
	2016								2015								2016		2015
(Dollars in Millions)	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total		Level 1		Level 1
Cash and cash equivalents	$	49	$	–	$	–	$	49	$	64	$	–	$	–	$	64	$	82	$	82
Debt securities		362		577		–		939		361		465		–		826		–		–
Corporate stock
Domestic equity securities		–		–		–		–		178		–		–		178		–		–
Mid-small cap equity securities(a)		–		–		–		–		146		–		–		146		–		–
International equity securities		–		–		–		–		123		–		–		123		–		–
Real estate equity securities(b)		169		–		–		169		163		–		–		163		–		–
Mutual funds
Debt securities		–		164		–		164		–		197		–		197		–		–
Emerging markets equity securities		–		155		–		155		–		81		–		81		–		–
Other		–		–		1		1		–		–		1		1		–		–
	$	580	$	896	$	1		1,477	$	1,035	$	743	$	1		1,779		82		82
Plan investment assets not classified in fair value hierarchy(e):
Collective investment funds
Domestic equity securities								977								679
Mid-small cap equity securities(c)								303								68
Emerging markets equity securities								–								75
International equity securities								725								533
Hedge funds(d)								188								171
Private equity funds								99								50
Total plan investment assets at fair value							$	3,769							$	3,355	$	82	$	82

(a) At December 31, 2015, securities included $139 million in domestic equities and $7 million in international equities.

(b) At December 31, 2016 and 2015, securities included $98 million and $90 million in domestic equities, respectively, and $71 million and $73 million in international equities, respectively.

(c) At December 31, 2016, securities included $303 million in domestic equities. At December 31, 2015, securities included $30 million in domestic equities, $20 million in international equities and $18 million in cash and cash equivalents.

(d) This category consists of several investment strategies diversified across several hedge fund managers.

(e) These investments are valued based on net asset value per share as a practical expedient; fair values are provided to reconcile to total investment assets of the plans at fair value.

Summarizes the Changes for Qualified Pension Plan Assets Measured at Fair Value Using Significant Unobservable Inputs (Level 3)

The following table summarizes the changes in fair value for qualified pension plan investment assets measured at fair value using significant unobservable inputs (Level 3) for the years ended December 31:

(Dollars in Millions)	2016		2015			2014
Balance at beginning of period	$	1	$	2		$	4
Unrealized gains (losses) relating to assets still held at end of year		–		(1	)		(2	)
Balance at end of period	$	1	$	1		$	2

Expected Future Benefit Payments

The following benefit payments are expected to be paid from the retirement plans for the years ended December 31:

(Dollars in Millions)	Pension Plans		Postretirement Welfare Plan(a)		Medicare Part D Subsidy Receipts
2017	$	191	$	10	$	2
2018		202		10		2
2019		215		10		2
2020		230		9		2
2021		244		9		2
2022 – 2026		1,448		33		5

(a) Net of expected retiree contributions and before Medicare Part D subsidy.