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, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Basic EPS:
Net income (loss)	$ (545)	$ 1,338	$ 10	$ 483	$ 476	$ (1,635)	$ 803	$ (676)
Basic weighted average common shares outstanding (in shares)	654,119			650,586			653,241	650,145
Basic EPS (in dollars per share)	$ (0.83)			$ 0.74			$ 1.23	$ (1.04)
Diluted EPS:
Interest expense on 6.50% convertible senior notes				$ 14			$ 33
Net income (loss) for purposes of computing diluted EPS	$ (545)			$ 497			$ 836	$ (676)
Dilutive effect of stock awards (in shares)	0			1,778			1,677	0
Dilutive effect of warrants (in shares)	0			1,893			3,310	0
Assumed conversion of 6.50% convertible senior notes (in shares)	0			61,728			61,728	0
Diluted weighted average common shares outstanding (in shares)	654,119			715,985			719,956	650,145
Diluted EPS (in dollars per share)	$ (0.83)			$ 0.69			$ 1.16	$ (1.04)
6.50% Senior Notes | Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Interest rate	6.50%						6.50%