Parent Company Financial Statements - Condensed Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investments in consolidated subsidiaries
Total assets	$ 208,264	$ 200,730
Liabilities
Long-term borrowings	8,201	3,965
Total liabilities	181,307	175,412
Shareholders’ equity	26,957	25,318	$ 17,903	$ 16,187
Total liabilities and shareholders’ equity	208,264	200,730
Parent Company [Member]
Assets
Cash in subsidiary bank	176	130
Due from consolidated bank subsidiaries
Money-market savings	3,223	1,690
Current income tax receivable	5	4
Total due from consolidated bank subsidiaries	3,228	1,694
Investments in consolidated subsidiaries
Banks	26,290	25,005
Other	391	380
Investments in trust preferred entities (note 20)	22	22
Other assets	100	93
Total assets	30,207	27,324
Liabilities
Accrued expenses and other liabilities	152	172
Long-term borrowings	3,098	1,834
Total liabilities	3,250	2,006
Shareholders’ equity	26,957	25,318
Total liabilities and shareholders’ equity	$ 30,207	$ 27,324