Fee-Based Revenue from Contracts with Customers - Retail Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Noninterest income	$ 1,872	$ 1,825
Retail Banking
Disaggregation of Revenue [Line Items]
Noninterest income	654	788
Retail Banking | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	484	526
Retail Banking | Out-of-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	170	262
Retail Banking | Debit card fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	138	129
Retail Banking | Deposit account fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	108	158
Retail Banking | Brokerage fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	102	93
Retail Banking | Net credit card fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	47	41
Interchange fees	120	118
Credit card reward costs	73	77
Retail Banking | Merchant services | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	32	49
Retail Banking | Other | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	$ 57	$ 56