v3.26.1
Derivative Instruments - Notional and Fair Value Position (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Derivative [Line Items]    
Notional Amount $ 693,854 $ 668,079
Asset Derivatives    
Derivative assets, gross amount offset (136) (199)
Derivative assets 352 177
Liability Derivatives    
Derivatives liabilities at fair value (676) (152)
Table Footnote [Abstract]    
Cash collateral posted for derivative instruments 1,200 1,100
Cash collateral received for derivative instruments 67 27
Total risk management derivatives designated as hedging instruments    
Derivative [Line Items]    
Notional Amount 438,273 477,083
Asset Derivatives    
Derivative assets, gross amount offset (136) (199)
Derivative assets 55 78
Liability Derivatives    
Netting adjustment 1,299 1,242
Derivatives liabilities at fair value (67) (14)
Total risk management derivatives designated as hedging instruments | Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 39,068 47,198
Asset Derivatives    
Derivative assets, gross 0 0
Liability Derivatives    
Derivative liabilities, gross 0 0
Total risk management derivatives designated as hedging instruments | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 399,205 429,885
Asset Derivatives    
Derivative assets, gross 191 277
Liability Derivatives    
Derivative liabilities, gross (1,366) (1,256)
Pay-fixed | Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 22,400 38,759
Asset Derivatives    
Derivative assets, gross 0 0
Liability Derivatives    
Derivative liabilities, gross 0 0
Pay-fixed | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 171,509 199,744
Asset Derivatives    
Derivative assets, gross 0 0
Liability Derivatives    
Derivative liabilities, gross 0 0
Receive-fixed | Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 16,668 8,439
Asset Derivatives    
Derivative assets, gross 0 0
Liability Derivatives    
Derivative liabilities, gross 0 0
Receive-fixed | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 189,110 194,394
Asset Derivatives    
Derivative assets, gross 79 145
Liability Derivatives    
Derivative liabilities, gross (1,177) (1,082)
Basis | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 250 250
Asset Derivatives    
Derivative assets, gross 32 28
Liability Derivatives    
Derivative liabilities, gross 0 0
Foreign currency | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 328 334
Asset Derivatives    
Derivative assets, gross 0 0
Liability Derivatives    
Derivative liabilities, gross (64) (56)
Pay-fixed | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 12,456 11,956
Asset Derivatives    
Derivative assets, gross 63 91
Liability Derivatives    
Derivative liabilities, gross (20) (4)
Receive-fixed | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 12,161 11,661
Asset Derivatives    
Derivative assets, gross 17 13
Liability Derivatives    
Derivative liabilities, gross (105) (114)
Futures | Not Designated as Hedging Instrument    
Derivative [Line Items]    
Notional Amount 13,391 11,546
Asset Derivatives    
Derivative assets, gross 0 0
Liability Derivatives    
Derivative liabilities, gross 0 0
Mortgage commitment derivatives    
Derivative [Line Items]    
Notional Amount 226,521 162,995
Asset Derivatives    
Derivative assets, gross amount offset 0 0
Derivative assets 259 55
Liability Derivatives    
Netting adjustment 0 0
Derivatives liabilities at fair value (593) (131)
Mortgage commitments to purchase whole loans    
Derivative [Line Items]    
Notional Amount 5,912 4,005
Asset Derivatives    
Derivative assets 9 7
Liability Derivatives    
Derivatives liabilities at fair value (20) (1)
Forward contracts to purchase mortgage-related securities    
Derivative [Line Items]    
Notional Amount 80,754 47,122
Asset Derivatives    
Derivative assets 138 48
Liability Derivatives    
Derivatives liabilities at fair value (158) (13)
Forward contracts to sell mortgage-related securities    
Derivative [Line Items]    
Notional Amount 139,855 111,868
Asset Derivatives    
Derivative assets 112 0
Liability Derivatives    
Derivatives liabilities at fair value (415) (117)
Credit enhancement derivatives    
Derivative [Line Items]    
Notional Amount 26,795 27,269
Asset Derivatives    
Derivative assets 38 44
Liability Derivatives    
Derivatives liabilities at fair value (3) (3)
Other derivatives    
Derivative [Line Items]    
Notional Amount 2,265 732
Asset Derivatives    
Derivative assets 0 0
Liability Derivatives    
Derivatives liabilities at fair value $ (13) $ (4)