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, 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
Asset Management Group [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	204	286	408	503
Asset Management Group [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	199	221	400	433
Asset Management Group [Member] | Out-of-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	5	65	8	70
Asset Management Group [Member] | Personal [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	151	157	301	304
Asset Management Group [Member] | Institutional [Member] | In-Scope [Member]
Disaggregation of Revenue [Line Items]
Noninterest income	$ 48	$ 64	$ 99	$ 129