Fee-based Revenue from Contracts with Customers - Retail Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 7,411	$ 7,221	$ 6,771
Retail Banking
Disaggregation of Revenue [Line Items]
Noninterest Income	2,631	$ 2,236	$ 2,693
Retail Banking | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	2,158
Retail Banking | Out-of-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	473
Retail Banking | Deposit Account Fees [Member] | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	618
Retail Banking | Debit Card Fees [Member] | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	505
Retail Banking | Brokerage Fees [Member] | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	350
Retail Banking | Merchant Fees [Member] | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	212
Retail Banking | Credit Card Fees, Net [Member] | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Interchange Fees	452
Noninterest Income	189
Credit Card Reward Costs	263
Retail Banking | Other | In-Scope Retail Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 284