Fair Value Measurements - Schedule of Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - Level 3 - Commodity Contracts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net liability balance at beginning of period	$ (1,044)	$ (1,219)	$ (360)
Total unrealized valuation gains (losses)	(175)	(765)	(1,382)
Purchases, issuances and settlements:
Purchases	266	222	185
Issuances	(26)	(30)	(62)
Settlements	137	136	345
Transfers into Level 3	(15)	(48)	(30)
Transfers out of Level 3	118	660	85
Net liabilities assumed in connection with the Energy Harbor Merger	(13)	0	0
Net change	292	175	(859)
Net liability balance at end of period	(752)	(1,044)	(1,219)
Unrealized valuation (losses) relating to instruments held at end of period	$ (416)	$ (676)	$ (977)