v3.26.1
Fair Value - Level 3 Valuation - Nonrecurring (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses $ 5,983 $ 5,464
Significant Unobservable Inputs (Level 3)    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for sale, at lower of cost or fair value 178 201
Nonrecurring | Significant Unobservable Inputs (Level 3)    
Fair Value Inputs, Quantitative Information [Line Items]    
Total assets at fair value 3,099 2,902
Nonrecurring | Significant Unobservable Inputs (Level 3) | Consensus    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for sale, at lower of cost or fair value 375 107
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net 371 402
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family | Internal Model    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses 211 221
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family | Accepted Offer and Appraisal    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net 155 139
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family | Internal Model and Walk Forward    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net 216 263
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses 1,856 2,068
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily | Internal Model    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses 212 250
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily | Appraisal    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses 208 231
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily | Asset Manager Estimate    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses 0 1
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily | Broker Price Opinion    
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses 1,436 1,586
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily | Broker Price Opinion and Appraisal    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net $ 286 $ 104