Outstanding Loans and Leases and Allowance for Credit Losses - Consumer Real Estate - Modification Programs (Details) - Consumer real estate - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	$ 1,206	$ 865	$ 715
Modifications under government programs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	2	4	13
Modifications under proprietary programs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	1,100	774	570
Loans discharged in Chapter 7 bankruptcy
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	14	33	53
Trial modifications
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total modifications	$ 90	$ 54	$ 79