Earnings Per Common Share - Computations of Diluted 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
Earnings Per Share [Abstract]
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
Adjusted 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)
Plus: Incremental shares from assumed conversion of stock-based compensation awards	708	478	667	577
Adjusted weighted-average shares outstanding (in shares)	167,659	166,320	167,372	167,359
Diluted earnings per common share (in USD per share)	$ 3.73	$ 5.05	$ 6.76	$ 9.06