Employee Benefit Plans - Defined Benefit Plan, Information about Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Significant Unobservable Inputs (Level 3)
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Settlements	$ 0	$ 0
Corporate | Significant Unobservable Inputs (Level 3)
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Settlements	0	0
Residential mortgage-backed securities ("RMBS") | Significant Unobservable Inputs (Level 3)
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Settlements	0	0
Foreign government/government agencies | Significant Unobservable Inputs (Level 3)
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Settlements	0	0
Mortgage loans | Significant Unobservable Inputs (Level 3)
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Settlements	0	0
Other investments | Significant Unobservable Inputs (Level 3)
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Settlements	0	0
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	4,363	3,914
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	4,363	3,914
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	4,482	4,363
Defined Benefit Plan, Fair Value of Plan Assets, Excluded Investment Payables	51	20
Pension Plan [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	859
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	859
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	501	859
Pension Plan [Member] | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,599
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,599
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,908	2,599
Pension Plan [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	210	160
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	210	160
Realized gains (losses), net	(3)	(1)
Changes in unrealized gains, net	0	6
Purchases	66	56
Sales	(23)	(9)
Transfers into Level 3	2	0
Transfers out of Level 3	(1)	(2)
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	251	210
Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	4,343
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	4,343
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 4,431	4,343
Pension Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	27.00%
Pension Plan [Member] | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	73.00%
Pension Plan [Member] | Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	$ 100
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	100
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	149	100
Pension Plan [Member] | Short-term Investments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	75
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	75
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	120	75
Pension Plan [Member] | Short-term Investments [Member] | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	25
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	25
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	29	25
Pension Plan [Member] | Short-term Investments [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Corporate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,342
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,342
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,375	2,342
Pension Plan [Member] | Corporate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Corporate | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,303
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,303
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,333	2,303
Pension Plan [Member] | Corporate | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	39	27
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	39	27
Realized gains (losses), net	0	0
Changes in unrealized gains, net	0	1
Purchases	6	14
Sales	(5)	(3)
Transfers into Level 3	2	0
Transfers out of Level 3		0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	42	39
Pension Plan [Member] | Residential mortgage-backed securities ("RMBS")
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	42
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	42
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	98	42
Pension Plan [Member] | Residential mortgage-backed securities ("RMBS") | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Residential mortgage-backed securities ("RMBS") | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	41
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	41
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	98	41
Pension Plan [Member] | Residential mortgage-backed securities ("RMBS") | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1	0
Realized gains (losses), net	0	0
Changes in unrealized gains, net	0	0
Purchases	0	1
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(1)	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	1
Pension Plan [Member] | U.S. Treasuries
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	47
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	47
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	192	47
Pension Plan [Member] | U.S. Treasuries | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	23	0
Pension Plan [Member] | U.S. Treasuries | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	47
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	47
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	169	47
Pension Plan [Member] | U.S. Treasuries | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Foreign government/government agencies
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	25
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	25
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	40	25
Pension Plan [Member] | Foreign government/government agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Foreign government/government agencies | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	38	16
Pension Plan [Member] | Foreign government/government agencies | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	9	1
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	9	1
Realized gains (losses), net	0	0
Changes in unrealized gains, net	0	0
Purchases	0	9
Sales	(7)	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	(1)
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2	9
Pension Plan [Member] | CMBS
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	30
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	30
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	60	30
Pension Plan [Member] | CMBS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | CMBS | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	30
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	30
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	56	30
Pension Plan [Member] | CMBS | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	4	0
Pension Plan [Member] | Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	137
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	137
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	186	137
Pension Plan [Member] | Other Fixed Income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Other Fixed Income [Member] | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	137
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	137
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	185	137
Pension Plan [Member] | Other Fixed Income [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	0
Pension Plan [Member] | Mortgage loans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	161
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	161
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	202	161
Pension Plan [Member] | Mortgage loans | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Mortgage loans | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Mortgage loans | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	161	131
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	161	131
Realized gains (losses), net	(3)	0
Changes in unrealized gains, net	0	4
Purchases	55	32
Sales	(11)	(6)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	202	161
Pension Plan [Member] | Domestic
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	513
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	513
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	237	513
Pension Plan [Member] | Domestic | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	513
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	513
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	237	513
Pension Plan [Member] | Domestic | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Domestic | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | International
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	271
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	271
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	121	271
Pension Plan [Member] | International | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	271
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	271
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	121	271
Pension Plan [Member] | International | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | International | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Pension Plan [Member] | Total pension plan assets at fair value, in the fair value hierarchy
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	3,668
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	3,668
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	3,660	3,668
Pension Plan [Member] | Total pension plan assets at fair value, in the fair value hierarchy | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	859
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	859
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	501	859
Pension Plan [Member] | Total pension plan assets at fair value, in the fair value hierarchy | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,599
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2,599
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,908	2,599
Pension Plan [Member] | Total pension plan assets at fair value, in the fair value hierarchy | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	210
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	210
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	251	210
Pension Plan [Member] | Private Market Alternatives
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	451
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	451
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	572	451
Pension Plan [Member] | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	224
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	224
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	199	224
Pension Plan [Member] | Other investments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0	1
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0	1
Realized gains (losses), net	0	(1)
Changes in unrealized gains, net	0	1
Purchases	5	0
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3		(1)
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	5	0
Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	1
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	63	75
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	63	75
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	51	63
Other Postretirement Benefits Plan [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	19
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	19
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	19	19
Other Postretirement Benefits Plan [Member] | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	44
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	44
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	32	44
Other Postretirement Benefits Plan [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 0	0
Other Postretirement Benefits Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	30.00%
Other Postretirement Benefits Plan [Member] | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	70.00%
Other Postretirement Benefits Plan [Member] | Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	$ 2
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	2
Other Postretirement Benefits Plan [Member] | Short-term Investments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	2
Other Postretirement Benefits Plan [Member] | Short-term Investments [Member] | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Short-term Investments [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Corporate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	11	16
Other Postretirement Benefits Plan [Member] | Corporate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Corporate | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	11	16
Other Postretirement Benefits Plan [Member] | Corporate | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Residential mortgage-backed securities ("RMBS")
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	9
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	9
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	7	9
Other Postretirement Benefits Plan [Member] | Residential mortgage-backed securities ("RMBS") | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Residential mortgage-backed securities ("RMBS") | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	9
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	9
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	7	9
Other Postretirement Benefits Plan [Member] | Residential mortgage-backed securities ("RMBS") | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | U.S. Treasuries
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	14	16
Other Postretirement Benefits Plan [Member] | U.S. Treasuries | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	0
Other Postretirement Benefits Plan [Member] | U.S. Treasuries | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	16
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	13	16
Other Postretirement Benefits Plan [Member] | U.S. Treasuries | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Foreign government/government agencies
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	0
Other Postretirement Benefits Plan [Member] | Foreign government/government agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	0
Other Postretirement Benefits Plan [Member] | Foreign government/government agencies | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Foreign government/government agencies | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | CMBS
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	1
Other Postretirement Benefits Plan [Member] | CMBS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | CMBS | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	1
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	1
Other Postretirement Benefits Plan [Member] | CMBS | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	2
Other Postretirement Benefits Plan [Member] | Other Fixed Income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Other Fixed Income [Member] | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	2
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1	2
Other Postretirement Benefits Plan [Member] | Other Fixed Income [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Large-cap
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	17
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	17
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	16	17
Other Postretirement Benefits Plan [Member] | Large-cap | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	17
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	17
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	16	17
Other Postretirement Benefits Plan [Member] | Large-cap | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Large-cap | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	0	0
Other Postretirement Benefits Plan [Member] | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Pension Plan Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance	0
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 0	$ 0
Minimum | Pension Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	3.00%
Minimum | Pension Plan [Member] | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	69.00%
Minimum | Pension Plan [Member] | Alternative assets
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	0.00%
Minimum | Other Postretirement Benefits Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	0.00%
Minimum | Other Postretirement Benefits Plan [Member] | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	55.00%
Minimum | Other Postretirement Benefits Plan [Member] | Alternative assets
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	0.00%
Maximum | Pension Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	23.00%
Maximum | Pension Plan [Member] | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	77.00%
Maximum | Pension Plan [Member] | Alternative assets
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	28.00%
Maximum | Other Postretirement Benefits Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	45.00%
Maximum | Other Postretirement Benefits Plan [Member] | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	100.00%
Maximum | Other Postretirement Benefits Plan [Member] | Alternative assets
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	0.00%