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, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2020
Basic EPS:
Net income (loss)	$ 483	$ 476	$ (1,635)	$ 169	$ 19	$ (1,250)	$ (676)	$ (1,061)
Basic weighted average common shares outstanding (in shares)	650,586			648,564			650,145	642,432
Basic EPS (in dollars per share)	$ 0.74			$ 0.26			$ (1.04)	$ (1.65)
Diluted EPS:
Interest expense on 6.50% convertible senior notes	$ 14			$ 14
Net income (loss) for purposes of computing diluted EPS	$ 497			$ 183			$ (676)	$ (1,061)
Dilutive effect of stock awards (in shares)	1,778			2,264			0	0
Dilutive effect of warrants (in shares)	1,893			8,586			0	0
Assumed conversion of 6.50% convertible senior notes (in shares)	61,728			61,728			0	0
Diluted weighted average common shares outstanding (in shares)	715,985			721,142			650,145	642,432
Diluted EPS (in dollars per share)	$ 0.69			$ 0.25			$ (1.04)	$ (1.65)
6.50% Senior Notes | Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Fixed interest rate per annum	6.50%						6.50%		6.50%