Earnings (Loss) Per Common Share - Computation of Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Basic EPS:
Net income (loss)	$ (114)	$ 599	$ (473)	$ (149)	$ 717	$ (312)	$ 12	$ 256
Weighted average common shares outstanding (in thousands), basic (in shares)	660,358			657,424			659,788	656,745
Basic EPS (in dollars per share)	$ (0.17)			$ (0.23)			$ 0.02	$ 0.39
Diluted EPS:
Net income (loss) for purposes of computing diluted EPS	$ (114)			$ (149)			$ 12	$ 256
Basic weighted average common shares outstanding (in shares)	660,358			657,424			659,788	656,745
Dilutive effect of restricted stock unit awards (in shares)	0			0			563	888
Dilutive effect of certain PSP Warrants and Treasury Loan Warrants (in shares)	0			0			433	1,142
Diluted weighted average common shares outstanding (in shares)	660,358			657,424			660,784	658,775
Diluted EPS (in dollars per share)	$ (0.17)			$ (0.23)			$ 0.02	$ 0.39