Income Taxes - Components of Deferred Tax Assets & Liabilities (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Liabilities
Property, plant and equipment and investments	$ (2,117)	$ (2,117)	$ (1,742)
Other	(108)	(108)	(99)
Total Deferred Tax Liabilities	(2,225)	(2,225)	(1,841)
Deferred Tax Assets
Net operating loss carryforwards	4,406	4,406	4,226
Tax credit carryforwards	109	109	98
Property, plant and equipment and investments	413	413	233
Accrued compensation, deferred credits and other liabilities	109	109	85
Asset retirement obligations	296	296	279
Other	256	256	293
Total Deferred Tax Assets	5,589	5,589	5,214
Valuation allowances	(3,652)	(3,652)	(3,658)
Total deferred tax assets, net of valuation allowances	1,937	1,937	1,556
Net Deferred Tax Assets (Liabilities)	(288)	(288)	(285)
Valuation allowance increase (decrease) amount	33	(6)	180	$ (1,553)
Deferred Tax Liabilities, Net [Abstract]
Deferred income taxes (long-term asset)	320	320	133
Deferred income taxes (long-term liability)	(608)	(608)	(418)
Net Deferred Tax Assets (Liabilities)	$ (288)	$ (288)	$ (285)