Legal Proceedings, Contingencies and Commitments - Summary of the Contractual Amount of Significant Commitments (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Mortgage loan commitments including interest rate locks
Loss Contingencies
Commitments to extend credit	$ 5,371	$ 5,539
Warehouse loan commitments
Loss Contingencies
Commitments to extend credit	7,675	6,840
Commercial and industrial commitments
Loss Contingencies
Commitments to extend credit	1,764	1,582
Other construction commitments
Loss Contingencies
Commitments to extend credit	2,877	2,719
HELOC commitments
Loss Contingencies
Commitments to extend credit	727	631
Other consumer commitments
Loss Contingencies
Commitments to extend credit	349	273
Standby and commercial letters of credit
Loss Contingencies
Commitments to extend credit	$ 102	$ 107