Accumulated Other Comprehensive Income AOCI by Component (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Beginning Balance	$ 194	$ 353
Other comprehensive income (loss), net before reclassifications	(1)	4
Reclassification from AOCI, Current Period, Tax	3
Ending Balance	187	358
Equity Method Investments
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Beginning Balance	9	(3)
Other comprehensive income (loss), net before reclassifications	(1)	4
Reclassification from AOCI, Current Period, Tax	0
Ending Balance	8	1
Pension and Retiree Health and Welfare Benefit Items
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Beginning Balance	185	356
Other comprehensive income (loss), net before reclassifications	0	0
Reclassification from AOCI, Current Period, Tax	3
Ending Balance	179	357
Amortization of net loss
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Amortization of actuarial losses	(9)	1
Amortization of net loss | Equity Method Investments
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Amortization of actuarial losses	0	0
Amortization of net loss | Pension and Retiree Health and Welfare Benefit Items
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Amortization of actuarial losses	$ (9)	$ 1