Earnings Per Common Share - Computation of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 597	$ 1,431	$ 1,877	$ 2,391
Dividends and undistributed earnings allocated to participating securities	(9)	(23)	(32)	(39)
Preferred stock dividends	(57)	(57)	(114)	(114)
Net income available to common stockholders	$ 531	$ 1,351	$ 1,731	$ 2,238
Total weighted-average basic common shares outstanding (in shares)	383,100,000	382,800,000	382,700,000	382,700,000
Effect of dilutive securities:
Stock options (in shares)	200,000	100,000	200,000	100,000
Other contingently issuable shares (in shares)	600,000	800,000	800,000	1,000,000.0
Total effect of dilutive securities (in shares)	800,000	900,000	1,000,000.0	1,100,000
Total weighted-average diluted common shares outstanding (in shares)	383,900,000	383,700,000	383,700,000	383,800,000
Basic earnings per common share:
Net income per basic common share (in dollars per share)	$ 1.39	$ 3.53	$ 4.52	$ 5.85
Diluted earnings per common share:
Net income per diluted common share (in dollars per share)	$ 1.38	$ 3.52	$ 4.51	$ 5.83
Award
Diluted earnings per common share:
Anti-dilutive options excluded from the computation of diluted earnings per share (in shares)	0	0	64,000	20,000