Noninterest Income - Lending Related Fees (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 21	$ 13	$ 55	$ 38
Unused commitment fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	14	10	42	27
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 7	$ 3	$ 13	$ 11