Fee-Based Revenue from Contracts with Customers - Retail Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Noninterest income	$ 1,549	$ 1,717	$ 3,374	$ 3,303
Retail Banking [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	585	657	1,373	1,252
Retail Banking [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	393	545	919	1,068
Retail Banking [Member] | Out-of-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	192	112	454	184
Retail Banking [Member] | Deposit Account Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	73	154	231	302
Retail Banking [Member] | Debit Card Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	120	136	249	260
Retail Banking [Member] | Brokerage Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	86	86	179	175
Retail Banking [Member] | Merchant Services [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	23	56	72	104
Retail Banking [Member] | Net Credit Card Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	39	51	80	99
Interchange fees	102	126	220	238
Credit card reward costs	63	75	140	139
Retail Banking [Member] | Other | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	$ 52	$ 62	$ 108	$ 128