Fee-Based Revenue from Contracts with Customers - Asset Management Group Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Noninterest income	$ 2,341	$ 1,797	$ 6,299	$ 5,171
Asset Management Fees
Disaggregation of Revenue [Line Items]
Noninterest income	248		713
Brokerage fees
Disaggregation of Revenue [Line Items]
Noninterest income	4		6
Asset Management Group
Disaggregation of Revenue [Line Items]
Noninterest income	256	221	729	629
Asset Management Group | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	252	215	719	615
Asset Management Group | Out-of-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	4	6	10	14
Asset Management Group | Personal | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	196	164	554	465
Asset Management Group | Institutional | In-Scope
Disaggregation of Revenue [Line Items]
Noninterest income	$ 56	$ 51	$ 165	$ 150