Fair Value of Assets and Liabilities - Schedule of Unobservable Inputs Utilized in Determining the Fair Value of Level 3 Recurring and Non-Recurring Measurements (Details) $ in Millions	Dec. 31, 2025 USD ($) month	Dec. 31, 2024 USD ($) month
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale at fair value	$ 8,165	$ 7,896
Loans held for sale (elected fair value)	151	85
Derivative liabilities, fair value	376	655
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, fair value	25	15
Loans and leases, fair value	370	344
OREO	$ 3	$ 3
Level 3 | Minimum | Visa covered litigation resolution amount | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	3,700	3,100
Level 3 | Minimum | Probability of resolution scenarios | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.10	0.10
Level 3 | Minimum | Time until resolution | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input | month	18	6
Level 3 | Minimum | Marketability adjustments for specific properties | Appraisals from comparable properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0	0
Level 3 | Minimum | Borrowing base certificates liquidation adjustment | Other collateral valuations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0.25	0.25
Level 3 | Minimum | Financial statements liquidation adjustment | Other collateral valuations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0.50	0.50
Level 3 | Minimum | Auction appraisals marketability adjustment | Other collateral valuations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0	0
Level 3 | Minimum | Adjustment for value changes since appraisal | Appraisals from comparable properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO measurement input	0	0
Level 3 | Maximum | Visa covered litigation resolution amount | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	4,500	4,100
Level 3 | Maximum | Probability of resolution scenarios | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.25	0.25
Level 3 | Maximum | Time until resolution | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input | month	48	36
Level 3 | Maximum | Marketability adjustments for specific properties | Appraisals from comparable properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0.25	0.25
Level 3 | Maximum | Borrowing base certificates liquidation adjustment | Other collateral valuations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0.50	0.50
Level 3 | Maximum | Financial statements liquidation adjustment | Other collateral valuations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	1	1
Level 3 | Maximum | Auction appraisals marketability adjustment | Other collateral valuations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, measurement input	0.10	0.10
Level 3 | Maximum | Adjustment for value changes since appraisal | Appraisals from comparable properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO measurement input	0.10	0.10
Level 3 | Weighted Average | Visa covered litigation resolution amount | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	4,200	3,800
Level 3 | Weighted Average | Probability of resolution scenarios | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.20	0.18
Level 3 | Weighted Average | Time until resolution | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input | month	35	23
Level 3 | SBA interest-only strips
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale at fair value	$ 45	$ 23
Level 3 | SBA interest-only strips | Minimum | Constant prepayment rate | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, measurement input	0.16	0.16
Level 3 | SBA interest-only strips | Minimum | Bond equivalent yield | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, measurement input	0.04	0.03
Level 3 | SBA interest-only strips | Maximum | Constant prepayment rate | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, measurement input	0.30	0.30
Level 3 | SBA interest-only strips | Maximum | Bond equivalent yield | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, measurement input	0.14	0.18
Level 3 | SBA interest-only strips | Weighted Average | Constant prepayment rate | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, measurement input	0.17	0.17
Level 3 | SBA interest-only strips | Weighted Average | Bond equivalent yield | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, measurement input	0.14	0.17
Level 3 | Loans Held For Sale, Residential Real Estate | Residential Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale (elected fair value)	$ 14	$ 16
Level 3 | Loans Held For Sale, Residential Real Estate | Minimum | Prepayment speeds - First mortgage | Discounted cash flow | Loans held for sale—first mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.02	0.02
Level 3 | Loans Held For Sale, Residential Real Estate | Minimum | Foreclosure losses | Discounted cash flow | Residential Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.64	0.63
Level 3 | Loans Held For Sale, Residential Real Estate | Minimum | Loss severity trends - First mortgage | Discounted cash flow | Loans held for sale—first mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.000	0.000
Level 3 | Loans Held For Sale, Residential Real Estate | Maximum | Prepayment speeds - First mortgage | Discounted cash flow | Loans held for sale—first mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.07	0.06
Level 3 | Loans Held For Sale, Residential Real Estate | Maximum | Foreclosure losses | Discounted cash flow | Residential Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.65	0.71
Level 3 | Loans Held For Sale, Residential Real Estate | Maximum | Loss severity trends - First mortgage | Discounted cash flow | Loans held for sale—first mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.013	0.002
Level 3 | Loans Held For Sale, Residential Real Estate | Weighted Average | Prepayment speeds - First mortgage | Discounted cash flow | Loans held for sale—first mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.03	0.03
Level 3 | Loans Held For Sale, Residential Real Estate | Weighted Average | Foreclosure losses | Discounted cash flow | Residential Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.64	0.64
Level 3 | Loans Held For Sale, Residential Real Estate | Weighted Average | Loss severity trends - First mortgage | Discounted cash flow | Loans held for sale—first mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.005	0.001