Asset Retirement Obligations - NPC - Change in Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	$ 1,340	$ 1,341
Change in estimated costs	2	81
Retirements	(122)	(144)
Accretion	47	47
Ending Balance	1,328	1,340
Other current liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	130
Ending Balance	76	130
Other long-term liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	1,210
Ending Balance	1,252	1,210
NPC
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	68	72
Change in estimated costs	5	0
Retirements	(16)	(6)
Accretion	2	2
Ending Balance	59	68
NPC | Other current liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	19
Ending Balance	16	19
NPC | Other long-term liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	49
Ending Balance	$ 43	$ 49