Noninterest Income - Client Investment 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
Sweep money market fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	10
Asset management fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	9
Repurchase agreement fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1
Client investment fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 35	$ 20