Fee-Based Revenue from Contracts with Customers - Asset Management Group Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Noninterest income	$ 1,941	$ 1,911	$ 3,752	$ 3,661
Asset Management Group [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	286	222	503	448
Asset Management Group [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	221	220	433	442
Asset Management Group [Member] | Out-of-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	65	2	70	6
Asset Management Group [Member] | Personal [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	157	152	304	306
Asset Management Group [Member] | Institutional [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	$ 64	$ 68	$ 129	$ 136