Noninterest Income - Foreign Exchange Fees (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 352	$ 327
Revenue not from contract with customer	165	417
Foreign exchange fees	73	57
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	66	55
Forward contract commissions
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	6	2
Option premium fees
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	$ 1	$ 0