v3.26.1
Commitments and Contingencies - Narrative (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
May 04, 2023
Loss Contingencies [Line Items]            
Basis spread on variable rate (percent) 0.15%   0.15%      
IDA balance floor amount           $ 60,000,000,000
IDA balance ceiling amount           $ 90,000,000,000
Additions (reductions) in deposit balance     $ 3,000,000,000.0      
Ending IDA balance $ 70,700,000,000   70,700,000,000   $ 76,300,000,000  
Fixed-rate obligation IDA balance 59,800,000,000   59,800,000,000   59,600,000,000  
Floating-rate obligation IDA balance 10,900,000,000   10,900,000,000   $ 16,700,000,000  
Guarantees            
Loss Contingencies [Line Items]            
Liability for guarantees 0   0      
Total residential real estate | First Mortgages            
Loss Contingencies [Line Items]            
Purchased during period 2,600,000,000 $ 1,700,000,000 4,600,000,000 $ 2,700,000,000    
Total residential real estate | HELOCs            
Loss Contingencies [Line Items]            
Purchased during period $ 71,000,000 $ 79,000,000 $ 133,000,000 $ 129,000,000