Stock-based Compensation Plans - Restricted Stock Activity (Detail) - Restricted Stock - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested at beginning of year, Restricted Stock	18	22	19
Granted, Restricted Stock	5	7	8
Adjustments for performance achieved, Restricted Stock	2	2
Vested, Restricted Stock	(11)	(13)	(5)
Unvested at year-end, Restricted Stock	14	18	22
Unvested at beginning of year, Weighted-Average Grant Date Fair Value	$ 30.24	$ 29.03	$ 35.24
Granted, Weighted-Average Grant Date Fair Value	56.24	36.16	25.16
Adjustments for performance achieved, Weighted-Average Grant Date Fair Value	32.47	35.55
Vested, Weighted-Average Grant Date Fair Value	29.82	32.42	48.44
Unvested at year-end, Weighted-Average Grant Date Fair Value	$ 39.88	$ 30.24	$ 29.03