Commitments and Contingencies - Commitments and Contingent Liabilities Outstanding (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Commitments to extend credit
Home equity lines of credit	$ 8,504,614	$ 5,693,045
Commercial real estate loans to be sold	568,799	324,943
Other commercial real estate	5,103,425	4,998,631
Residential real estate loans to be sold	69,089	233,257
Other residential real estate	1,178,317	924,211
Commercial and other	31,065,311	22,145,057
Standby letters of credit	2,342,713	2,151,595
Commercial letters of credit	52,816	31,981
Financial guarantees and indemnification contracts	4,103,744	4,211,797
Commitments to sell real estate loans	$ 908,436	$ 1,367,523