v3.26.1
Fair Value Measurements - Fair Values of Assets and Liabilities (Significant Unobservable Level 3 Inputs Recurring Basis) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Derivative Assets $ 3,330   $ 1,868
Derivative liabilities (3,501)   (2,034)
Servicing rights      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Servicing rights $ 1,583 $ 1,663  
Servicing rights | Minimum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Prepayment speed 0.00% 0.00%  
OAS (bps) 0.0335 0.0335  
Servicing rights | Maximum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Prepayment speed 90.30% 100.00%  
OAS (bps) 0.1827 0.1821  
Servicing rights | Fixed | Weighted-Average      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Prepayment speed 6.80% 6.30%  
OAS (bps) 0.0431 0.0418  
Servicing rights | Adjustable | Weighted-Average      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Prepayment speed 18.70% 16.00%  
OAS (bps) 0.0711 0.0725  
IRLCs, net      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Derivative Assets $ 6 $ 5  
IRLCs, net | Minimum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Loan closing rates 0.80% 20.50%  
IRLCs, net | Maximum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Loan closing rates 98.80% 96.00%  
IRLCs, net | Weighted-Average      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Loan closing rates 84.90% 79.70%  
Swap      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Derivative liabilities $ (82) $ (173)  
Swap | Minimum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Timing of the resolution of the Covered Litigation Mar. 31, 2028 Jun. 30, 2027  
Swap | Maximum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Timing of the resolution of the Covered Litigation Jun. 30, 2029 Mar. 31, 2028  
Swap | Weighted-Average      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Timing of the resolution of the Covered Litigation Sep. 30, 2028 Dec. 31, 2027  
Residential Mortgage      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Loans measured at FV $ 105 $ 109 $ 106
Residential Mortgage | Minimum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Interest rate risk factor (52.00%) (51.90%)  
Credit risk factor 0.00% 0.00%  
Residential Mortgage | Maximum      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Interest rate risk factor 7.20% 5.70%  
Credit risk factor 0.70% 0.70%  
Residential Mortgage | Weighted-Average      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis      
Interest rate risk factor (10.10%) (11.50%)  
Credit risk factor 0.10% 0.10%