Earnings Per Common Share - Schedule of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
(Loss) Income (numerator)
Net (loss) income	$ (8,736)	$ 344	$ (8,225)	$ 943
Net (loss) income applicable to common stock for computing basic (loss) earnings per common share	(8,736)	344	(8,225)	943
Net (loss) income as adjusted for purposes of computing diluted (loss) earnings per common share	$ (8,736)	$ 344	$ (8,225)	$ 943
Weighted-average number of shares:
Outstanding during period (in shares)	1,006,229	1,033,060	1,004,948	1,030,138
Non-vested restricted stock (in shares)	(22,776)	(20,117)	(22,443)	(19,452)
Weighted average shares outstanding for computing basic (loss) earnings per common share (in shares)	983,453	1,012,943	982,505	1,010,686
Incremental common shares attributable to dilutive securities:
Shares issuable under convertible securities (in shares)	0	10	0	10
Shares issuable under incentive compensation plans (in shares)	0	3,667	0	5,221
Number of shares as adjusted for purposes of computing diluted (loss) earnings per common share (in shares)	983,453	1,016,620	982,505	1,015,917
Basic (loss) earnings per common share (in dollars per share)	$ (8.88)	$ 0.34	$ (8.37)	$ 0.93
Diluted (loss) earnings per common share (in dollars per share)	$ (8.88)	$ 0.34	$ (8.37)	$ 0.93