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		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings
Net income	$ 651	$ 340	$ 1,733	$ 1,227
Less: Preferred stock dividends	6	6	16	16
Net income available to common stockholders	$ 645	$ 334	$ 1,717	$ 1,211
Shares
Weighted average common shares outstanding, basic	304.6	322.1	309.3	327.3
Dilutive effect of stock-based awards under compensation plans	4.4	4.2	4.3	4.5
Weighted average common shares outstanding and dilutive potential common shares	309.0	326.3	313.6	331.8
Earnings Per Share, Basic [Abstract]
Net income available to common stockholders	$ 2.12	$ 1.04	$ 5.55	$ 3.70
Earnings Per Share, Diluted [Abstract]
Net income available to common stockholders	$ 2.09	$ 1.02	$ 5.48	$ 3.65