Loans and Related Allowance for Credit Losses, Troubled Debt Restructurings, Current Defaults (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	$ 69	$ 83
Total Commercial [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	51	57
Commercial and industrial loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	49	41
Real estate mortgage [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	2	16
Real estate construction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	0	0
Lease financing [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	0	0
Total Consumer [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	18	26
Residential mortgage - first lien [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	7	3
Residential mortgage - junior lien [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	0	1
Credit card [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	5	10
Auto [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	6	11
Other consumer [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded investment of defaults	$ 0	$ 1