Earnings Per Common Share - Computations of Basic Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Income available to common shareholders:
Net income	$ 584	$ 531
Less: Preferred stock dividends	(36)	(25)
Net income available to common equity	548	506
Less: Income attributable to unvested stock-based compensation awards	(1)	(1)
Net income available to common shareholders	$ 547	$ 505
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	164,520	166,738
Less: Unvested stock-based compensation awards	(311)	(278)
Weighted-average shares outstanding (in shares)	164,209	166,460
Basic earnings per common share (in USD per share)	$ 3.33	$ 3.04