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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Noninterest income	$ 2,086	$ 1,549	$ 3,958	$ 3,374
Asset Management Group
Disaggregation of Revenue [Line Items]
Noninterest income	244	204	473	408
Asset Management Group | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	241	199	467	400
Asset Management Group | Out-of-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	3	5	6	8
Asset Management Group | Personal | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	185	151	358	301
Asset Management Group | Institutional | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	$ 56	$ 48	$ 109	$ 99