Revenue from Contracts with Customers (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 1,823,000,000	$ 1,428,000,000
Other noninterest income	1,234,000,000	1,095,000,000
Noninterest income	3,194,000,000	2,652,000,000	$ 2,459,000,000
Contract assets	0	0
Contract liabilities	0	0
Trust and investment services income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	484,000,000	441,000,000
Investment banking and debt placement fees
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	586,000,000	305,000,000
Services charges on deposit accounts
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	337,000,000	311,000,000
Cards and payments income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	407,000,000	361,000,000
Other noninterest income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	9,000,000	10,000,000
Operating Segments | Consumer Bank
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	806,000,000	733,000,000
Noninterest income	1,068,000,000	999,000,000	917,000,000
Operating Segments | Consumer Bank | Trust and investment services income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	417,000,000	374,000,000
Operating Segments | Consumer Bank | Investment banking and debt placement fees
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
Operating Segments | Consumer Bank | Services charges on deposit accounts
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	201,000,000	189,000,000
Operating Segments | Consumer Bank | Cards and payments income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	181,000,000	160,000,000
Operating Segments | Consumer Bank | Other noninterest income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	7,000,000	10,000,000
Operating Segments | Commercial Bank
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,017,000,000	695,000,000
Noninterest income	1,989,000,000	1,524,000,000	1,395,000,000
Operating Segments | Commercial Bank | Trust and investment services income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	67,000,000	67,000,000
Operating Segments | Commercial Bank | Investment banking and debt placement fees
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	586,000,000	305,000,000
Operating Segments | Commercial Bank | Services charges on deposit accounts
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	136,000,000	122,000,000
Operating Segments | Commercial Bank | Cards and payments income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	226,000,000	201,000,000
Operating Segments | Commercial Bank | Other noninterest income
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,000,000	0
Other
Disaggregation of Revenue [Line Items]
Noninterest income	$ 137,000,000	$ 129,000,000	$ 147,000,000