Fee-Based Revenue from Contracts with Customers - Retail Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Noninterest income	$ 2,341	$ 1,797	$ 6,299	$ 5,171
Brokerage fees
Disaggregation of Revenue [Line Items]
Noninterest income	4		6
Retail Banking
Disaggregation of Revenue [Line Items]
Noninterest income	662	673	2,022	2,046
Retail Banking | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	624	490	1,670	1,409
Retail Banking | Out-of-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	38	183	352	637
Retail Banking | Debit card fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	184	136	486	385
Retail Banking | Deposit account fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	142	108	367	339
Retail Banking | Brokerage fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	123	94	334	273
Retail Banking | Net credit card fees | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	53	50	157	130
Interchange fees	155	121	421	341
Credit card reward costs	102	71	264	211
Retail Banking | Merchant services | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	46	40	125	112
Retail Banking | Other | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	$ 76	$ 62	$ 201	$ 170