Other Income and Other Expense - Other Income and Other Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other revenues from operations:
Credit-related fee income	$ 151	$ 130	$ 91
Credit card interchange fee income			70
Merchant discount fee income			61
Other costs of operations:
Amortization of capitalized mortgage servicing rights	131	97	$ 90
Charitable contributions		178
CIT [Member]
Other revenues from operations:
Gain on divestiture	$ 225
MTLA [Member]
Other revenues from operations:
Gain on divestiture		$ 136