Income Taxes - Components of Deferred Tax Assets & Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Liabilities
Property, plant and equipment and investments	$ (2,320)	$ (2,117)
Other	(101)	(108)
Total Deferred Tax Liabilities	(2,421)	(2,225)
Deferred Tax Assets
Net operating loss carryforwards	4,432	4,406
Tax credit carryforwards	109	109
Property, plant and equipment and investments	641	413
Accrued compensation, deferred credits and other liabilities	101	109
Asset retirement obligations	313	296
Other	339	256
Total Deferred Tax Assets	5,935	5,589
Valuation allowances	(3,719)	(3,652)
Total deferred tax assets, net of valuation allowances	2,216	1,937
Net Deferred Tax Assets (Liabilities)	(205)	(288)
Valuation allowance increase (decrease) amount	(67)	6	$ (180)
Deferred Tax Liabilities, Net [Abstract]
Deferred income taxes (long-term asset)	579	320
Deferred income taxes (long-term liability)	(784)	(608)
Net Deferred Tax Assets (Liabilities)	$ (205)	$ (288)