Earnings (Loss) Per Common Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings
Net income	$ 547	$ 444	$ 1,082	$ 887
Less: Preferred stock dividends	5	5	10	10
Net income available to common stockholders	$ 542	$ 439	$ 1,072	$ 877
Shares
Weighted average common shares outstanding, basic	309.4	327.4	311.7	329.9
Dilutive effect of stock-based awards under compensation plans	3.9	4.4	4.3	4.7
Weighted average common shares outstanding and dilutive potential common shares	313.3	331.8	316.0	334.6
Earnings Per Share, Basic [Abstract]
Net income available to common stockholders	$ 1.75	$ 1.34	$ 3.44	$ 2.66
Earnings Per Share, Diluted [Abstract]
Net income available to common stockholders	$ 1.73	$ 1.32	$ 3.39	$ 2.62