v3.26.1
Fair Value - Level 3 Valuation - Nonrecurring (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value Inputs, Quantitative Information [Line Items]    
Mortgage loans held for investment, net of allowance for loan losses $ 5,547 $ 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 191 201
Nonrecurring | Significant Unobservable Inputs (Level 3)    
Fair Value Inputs, Quantitative Information [Line Items]    
Total assets at fair value 1,993 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 90 107
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net 202 402
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 214 221
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family | Accepted Offer and Appraisal    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net 90 139
Nonrecurring | Significant Unobservable Inputs (Level 3) | Single-Family | Internal Model and Walk Forward    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net 112 263
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 1,195 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 188 250
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 38 231
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 969 1,586
Nonrecurring | Significant Unobservable Inputs (Level 3) | Multifamily | Broker Price Opinion and Appraisal    
Fair Value Inputs, Quantitative Information [Line Items]    
Acquired property, net $ 292 $ 104