Fee-Based Revenue from Contracts with Customers - Retail Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Noninterest income	$ 2,086	$ 1,549	$ 3,958	$ 3,374
Brokerage fees
Disaggregation of Revenue [Line Items]
Noninterest income	2		2
Retail Banking
Disaggregation of Revenue [Line Items]
Noninterest income	706	585	1,360	1,373
Retail Banking | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	562	393	1,046	919
Retail Banking | Out-of-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	144	192	314	454
Retail Banking | Debit card fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	164	120	302	249
Retail Banking | Deposit account fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	117	73	225	231
Retail Banking | Brokerage fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	109	86	211	179
Retail Banking | Net credit card fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	57	39	104	80
Interchange fees	146	102	266	220
Credit card reward costs	89	63	162	140
Retail Banking | Merchant services | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	47	23	79	72
Retail Banking | Other | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	$ 68	$ 52	$ 125	$ 108