Fee-Based Revenue from Contracts with Customers - Retail Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Noninterest income	$ 1,989	$ 1,891	$ 5,741	$ 5,552
Retail Banking [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	744	622	1,996	1,935
Retail Banking [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	567	548	1,635	1,594
Retail Banking [Member] | Out-of-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	177	74	361	341
Retail Banking [Member] | Deposit Account Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	166	162	468	451
Retail Banking [Member] | Debit Card Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	139	130	399	374
Retail Banking [Member] | Brokerage Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	92	86	267	260
Retail Banking [Member] | Merchant Services [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	55	54	159	156
Retail Banking [Member] | Net Credit Card Fees [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	50	45	149	139
Interchange fees	128	115	366	332
Credit card reward costs	78	70	217	193
Retail Banking [Member] | Other [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	$ 65	$ 71	$ 193	$ 214