Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Abstract]

Changes in benefit obligations and plan assets [Table Text Block]

The following table presents the changes in benefit obligations and plan assets for pension benefits and other postretirement benefits for the years indicated:

	Pension Benefits				Other Postretirement Benefits
	2020		2019		2020		2019
	(Millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	1,237	$	1,187	$	215	$	186
Service cost	31		45		1		1
Interest cost	36		50		7		8
Plan participants’ contributions	—		—		2		2
Benefits paid	(41)		(111)		(14)		(12)
Net actuarial loss (gain)	47		69		9		30
Settlements	(127)		(3)		—		—
Net increase (decrease) in benefit obligation	(54)		50		5		29
Benefit obligation at end of year	1,183		1,237		220		215
Change in plan assets:
Fair value of plan assets at beginning of year	1,299		1,132		247		214
Actual return on plan assets	212		218		37		38
Employer contributions	14		63		6		5
Plan participants’ contributions	—		—		2		2
Benefits paid	(41)		(111)		(14)		(12)
Settlements	(127)		(3)		—		—
Net increase (decrease) in fair value of plan assets	58		167		31		33
Fair value of plan assets at end of year	1,357		1,299		278		247
Funded status — overfunded (underfunded)	$	174	$	62	$	58	$	32
Accumulated benefit obligation	$	1,167	$	1,221

Overfunded (underfunded) status of our pension plans and other postretirement benefit plans [Table Text Block]

The overfunded (underfunded) status of our pension plans and other postretirement benefit plan presented in the previous table are recognized in the Consolidated Balance Sheet within the following accounts:

	December 31,
	2020		2019
	(Millions)
Overfunded (underfunded) pension plans:
Noncurrent assets	$	203	$	92
Current liabilities	(3)		(3)
Noncurrent liabilities	(26)		(27)
Overfunded (underfunded) other postretirement benefit plan:
Noncurrent assets	64		38
Current liabilities	(6)		(6)

Defined Benefit Plan, Plan with Projected Benefit Obligation in Excess of Plan Assets [Table Text Block]

The following table summarizes information for pension plans with obligations in excess of plan assets.

	December 31,
	2020		2019
	(Millions)
Plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	$	29	$	29
Fair value of plan assets	—		—
Plans with an accumulated benefit obligation in excess of plan assets:
Accumulated benefit obligation	25		26
Fair value of plan assets	—		—

Pre-tax amounts not yet recognized in net periodic benefit cost (credit)[Table Text Block]

Pre-tax amounts not yet recognized in Net periodic benefit cost (credit) at December 31 are as follows: 

	Pension Benefits				Other Postretirement Benefits
	2020		2019		2020		2019
	(Millions)
Amounts included in Accumulated other comprehensive income (loss):
Net actuarial loss	$	(101)	$	(243)	$	(25)	$	(21)
Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline:
Net actuarial gain	N/A		N/A		$	32	$	11

Schedule of Net Benefit Cost (Credit) [Table Text Block]

Net periodic benefit cost (credit) for the years ended December 31 consist of the following:

	Pension Benefits						Other Postretirement  Benefits
	2020		2019		2018		2020		2019		2018
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	31	$	45	$	50	$	1	$	1	$	1
Interest cost	36		50		46		7		8		7
Expected return on plan assets	(53)		(61)		(63)		(11)		(10)		(11)
Amortization of prior service credit	—		—		—		—		—		(2)
Amortization of net actuarial loss	21		15		23		—		—		—
Net actuarial loss from settlements	9		1		23		—		—		—
Reclassification to regulatory liability	—		—		—		2		1		2
Net periodic benefit cost (credit)	$	44	$	50	$	79	$	(1)	$	—	$	(3)

Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) [Table Text Block]

Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) before taxes for the years ended December 31 consist of the following:

	Pension Benefits						Other Postretirement  Benefits
	2020		2019		2018		2020		2019		2018
	(Millions)
Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss):
Net actuarial gain (loss)	$	112	$	88	$	(18)	$	(4)	$	(9)	$	9
Amortization of net actuarial loss	21		15		23		—		—		—
Net actuarial loss from settlements	9		1		23		—		—		—
Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss)	$	142	$	104	$	28	$	(4)	$	(9)	$	9

Schedule of Regulatory Assets / Liabilities [Table Text Block]

Other changes in plan assets and benefit obligations for our other postretirement benefit plan associated with Transco and Northwest Pipeline are recognized in regulatory assets and liabilities. Amounts recognized in regulatory assets and liabilities for the years ended December 31 consist of the following:

	2020		2019		2018
	(Millions)
Other changes in plan assets and benefit obligations recognized in regulatory (assets) and liabilities:
Net actuarial gain (loss)	$	21	$	7	$	(10)
Amortization of prior service credit	—		—		(2)

Defined Benefit Plan, Assumptions [Table Text Block]

The weighted-average assumptions utilized to determine benefit obligations as of December 31 are as follows: 

	Pension Benefits				Other Postretirement Benefits
	2020		2019		2020		2019
Discount rate	2.45	%	3.19	%	2.59	%	3.27	%
Rate of compensation increase	3.76		3.68		N/A		N/A
Cash balance interest crediting rate	3.00		3.50		N/A		N/A

The weighted-average assumptions utilized to determine Net periodic benefit cost (credit) for the years ended December 31 are as follows: 

	Pension Benefits						Other Postretirement  Benefits
	2020		2019		2018		2020		2019		2018
Discount rate	3.08	%	4.33	%	3.67	%	3.27	%	4.39	%	3.71	%
Expected long-term rate of return on plan assets	4.67		5.26		5.34		4.39		5.01		4.95
Rate of compensation increase	3.68		4.83		4.93		N/A		N/A		N/A
Cash balance interest crediting rate	3.50		4.25		4.25		N/A		N/A		N/A

Fair values of plan assets [Table Text Block]

The fair values of our pension plan assets at December 31, 2020 and 2019 by asset class are as follows: 

	2020
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(Millions)
Pension assets:
Cash management fund	$	21	$	—	$	—	$	21
Equity securities	39		22		—		61
Fixed income securities (1):
U.S. Treasury securities	110		—		—		110
Government and municipal bonds	—		32		—		32
Mortgage and asset-backed securities	—		19		—		19
Corporate bonds	—		342		—		342
Other	—		4		—		4
	$	170	$	419	$	—	589
Commingled investment funds measured at net asset value practical expedient (2):
Equities — U.S. large cap							137
Equities — Global large and mid cap							121
Equities — International emerging markets							30
Fixed income — U.S. long and intermediate duration							346
Fixed income — Corporate bonds							134
Total assets at fair value at December 31, 2020							$	1,357

	2019
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(Millions)
Pension assets:
Cash management fund	$	11	$	—	$	—	$	11
Equity securities	41		22		—		63
Fixed income securities (1):
U.S. Treasury securities	62		—		—		62
Government and municipal bonds	—		35		—		35
Mortgage and asset-backed securities	—		11		—		11
Corporate bonds	—		360		—		360
Other	5		4		—		9
	$	119	$	432	$	—	551
Commingled investment funds measured at net asset value practical expedient (2):
Equities — U.S. large cap							133
Equities — Global large and mid cap							100
Equities — International emerging markets							26
Fixed income — U.S. long and intermediate duration							380
Fixed income — Corporate bonds							109
Total assets at fair value at December 31, 2019							$	1,299

The fair values of our other postretirement benefits plan assets at December 31, 2020 and 2019 by asset class are as follows:

	2020
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(Millions)
Other postretirement benefit assets:
Cash management funds	$	12	$	—	$	—	$	12
Equity securities	38		10		—		48
Fixed income securities (1):
U.S. Treasury securities	14		—		—		14
Government and municipal bonds	—		4		—		4
Mortgage and asset-backed securities	—		3		—		3
Corporate bonds	—		45		—		45
Mutual fund — Municipal bonds	52		—		—		52
	$	116	$	62	$	—	178
Commingled investment funds measured at net asset value practical expedient (2):
Equities — U.S. large cap							18
Equities — Global large and mid cap							16
Equities — International emerging markets							4
Fixed income — U.S. long and intermediate duration							45
Fixed income — Corporate bonds							17
Total assets at fair value at December 31, 2020							$	278

	2019
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(Millions)
Other postretirement benefit assets:
Cash management funds	$	11	$	—	$	—	$	11
Equity securities	35		9		—		44
Fixed income securities (1):
U.S. Treasury securities	8		—		—		8
Government and municipal bonds	—		4		—		4
Mortgage and asset-backed securities	—		1		—		1
Corporate bonds	—		43		—		43
Mutual fund — Municipal bonds	46		—		—		46
	$	100	$	57	$	—	157
Commingled investment funds measured at net asset value practical expedient (2):
Equities — U.S. large cap							16
Equities — Global large and mid cap							12
Equities — International emerging markets							3
Fixed income — U.S. long and intermediate duration							46
Fixed income — Corporate bonds							13
Total assets at fair value at December 31, 2019							$	247

____________

(1)The weighted-average credit quality rating of the fixed income security portfolio is investment grade with a weighted-average duration of approximately 16 years for 2020 and 14 years for 2019.

(2)    The stated intents of the funds vary based on each commingled fund’s investment objective. These objectives generally include strategies to replicate or outperform various market indices. Certain standard withdrawal restrictions generally apply, which may include redemption notification period restrictions ranging from 1 day to 30 days. Additionally, the fund managers retain the right to restrict withdrawals from and/or purchases into the funds so as not to disadvantage other investors in the funds. Generally, the funds also reserve the right to make all or a portion of the redemption in-kind rather than in cash or a combination of cash and in-kind.

Expected benefit payments [Table Text Block]

Following are the expected benefits to be paid by the plans. These estimates are based on the same assumptions previously discussed and reflect future service as appropriate. The actuarial assumptions are based on long-term expectations and include, but are not limited to, assumptions as to average expected retirement age and form of benefit payment. Actual benefit payments could differ significantly from expected benefit payments if near-term participant behaviors differ significantly from the actuarial assumptions. 

	Pension Benefits		Other Postretirement Benefits
	(Millions)
2021	$	96	$	14
2022	91		14
2023	86		14
2024	82		13
2025	82		13
2026-2030	378		57