Accumulated Other Comprehensive Income Reclassifications out of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Balance	$ 353	$ 98	$ 145
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(163)	251	(47)
Reclassification AOCI, Tax	(1)	(1)	(1)
Balance	194	353	98
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(56)	81	(17)
Amortization of net gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income	6
Amortization of prior service credits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income		6
Settlement (gain) lossa
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income	(1)	(1)	(1)
Equity Method Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Balance	(3)	(3)	(4)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	12	0	1
Reclassification AOCI, Tax	0	0	0
Balance	9	(3)	(3)
Equity Method Investments | Amortization of net gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income	0
Equity Method Investments | Amortization of prior service credits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income		0
Equity Method Investments | Settlement (gain) lossa
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income	0	0	0
Pension and Retiree Health and Welfare Benefit Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Balance	356	101	149
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(175)	251	(48)
Reclassification AOCI, Tax	(1)	(1)	(1)
Balance	185	356	101
Pension and Retiree Health and Welfare Benefit Items | Amortization of net gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income	6
Pension and Retiree Health and Welfare Benefit Items | Amortization of prior service credits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income		6
Pension and Retiree Health and Welfare Benefit Items | Settlement (gain) lossa
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income	$ (1)	$ (1)	$ (1)