Accumulated Other Comprehensive Income AOCI by Component (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Beginning Balance	$ 353	$ 98
Other comprehensive income (loss), net before reclassifications	4	0
Ending Balance	358	99
Equity Method Investments
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Beginning Balance	(3)	(3)
Other comprehensive income (loss), net before reclassifications	4	0
Ending Balance	1	(3)
Pension and Retiree Health and Welfare Benefit Items
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Beginning Balance	356	101
Other comprehensive income (loss), net before reclassifications	0	0
Ending Balance	357	102
Amortization of net loss
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Amortization of actuarial losses	1	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	$ 1	$ 1