Commitments and Contingencies - Commitments and Contingent Liabilities Outstanding (Detail) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Commitments to extend credit
Commercial and industrial	$ 28,439	$ 28,566
Commercial real estate loans to be sold	451	916
Other commercial real estate	4,413	5,019
Residential real estate loans to be sold	211	163
Other residential real estate	393	331
Home equity lines of credit	8,080	8,109
Credit cards	5,651	5,578
Other	389	413
Standby letters of credit	2,230	2,289
Commercial letters of credit	56	62
Financial guarantees and indemnification contracts	4,129	4,036
Commitments to sell real estate loans	$ 1,329	$ 1,400