Noninterest Income - Credit Card Fees (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Card interchange fees, net	$ 30	$ 23
Revenue from contracts with customers	352	327
Revenue not from contract with customer	165	417
Total credit card fees	37	28
Merchant service fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	4
Card service fees
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	$ 2	$ 1