Strategic Initiatives - Expected Charges (Details) - Restructuring Plan $ in Millions	Mar. 31, 2022 USD ($)
Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	$ 780
Minimum | Wealth and Personal Banking
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	175
Minimum | Commercial Banking
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	8
Minimum | Markets and Securities Services
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	82
Minimum | Global Banking and Markets Other
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	14
Minimum | Corporate Center
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	501
Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	860
Maximum | Wealth and Personal Banking
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	195
Maximum | Commercial Banking
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	10
Maximum | Markets and Securities Services
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	88
Maximum | Global Banking and Markets Other
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	16
Maximum | Corporate Center
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	$ 551