Earnings Per Common Share - Computations of Basic Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income available to common shareholders:
Net income	$ 655	$ 867	$ 1,186	$ 1,569
Less: Preferred stock dividends	(27)	(25)	(52)	(50)
Net income available to common equity	628	842	1,134	1,519
Less: Income attributable to unvested stock-based compensation awards	(2)	(1)	(3)	(3)
Net income available to common shareholders	$ 626	$ 841	$ 1,131	$ 1,516
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	167,282	166,152	167,010	167,076
Less: Unvested stock-based compensation awards	(331)	(310)	(305)	(294)
Weighted-average shares outstanding (in shares)	166,951	165,842	166,705	166,782
Basic earnings per common share (in USD per share)	$ 3.75	$ 5.07	$ 6.79	$ 9.09