Outstanding Loans and Leases and Allowance for Credit Losses - Consumer Real Estate - Modification Programs (Details) - Consumer real estate - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	$ 599	$ 513	$ 914	$ 730
Modifications under government programs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	0	1	0	3
Modifications under proprietary programs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	536	479	816	665
Loans discharged in Chapter 7 bankruptcy
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	4	12	8	22
Trial modifications
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	$ 59	$ 21	$ 90	$ 40