v3.26.1
Derivative and Other Hedging Instruments (Effect Of Derivative Instruments Not Designated As Hedges On Comprehensive Income Statement) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Amount Gain/(Loss) Recognized in Income on Derivatives $ 487 $ (369) $ 869 $ (1,380)        
Interest Rate Swaption [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount   (2,000)   (2,000)     $ (2,000)  
Additions   0   1,500        
Settlement, Expirations or Exercise   0   (1,500)        
Amount Gain/(Loss) Recognized in Income on Derivatives   (9)   (28)        
TBA and Forward Settling Agency Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (10,047) (8,407) (10,047) (8,407) $ (10,909) $ (13,180) (7,811) $ (6,955)
Additions 51,648 35,699 105,065 63,666        
Settlement, Expirations or Exercise       (62,214)        
Amount Gain/(Loss) Recognized in Income on Derivatives (36) 11 (90) 88        
Purchases Of TBAs And Forward Settling Agency Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Settlement, Expirations or Exercise (52,510) (35,103) (108,198)          
Interest Rate Swap [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Additions 400 2,600 51,020 10,750        
Settlement, Expirations or Exercise (3,150) (5,300) (41,900) (5,300)        
Notional Amount (73,752)   (73,752)          
Amount Gain/(Loss) Recognized in Income on Derivatives 640 (236) 1,095 (805)        
Receiver Swaption [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (7,750) (150) (7,750) (150) (7,000) (7,000) (150) (150)
Additions 3,750 0 3,750 0        
Settlement, Expirations or Exercise 3,000 0 3,000 0        
Amount Gain/(Loss) Recognized in Income on Derivatives (15) 0 (21) 0        
SOFR Futures Contracts                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (2,600) (1,200) (2,600) (1,200)        
Not Designated as Hedging Instrument [Member] | Interest Rate Swaption [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount               (2,000)
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (73,752) (45,096) (73,752) (45,096) (76,502) (64,632) (47,796) (39,646)
Short [Member] | US Treasury Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (18,370) (21,396) (18,370) (21,396) (17,162) (16,378) (17,636) (17,792)
Additions 5,340 7,971 10,339 11,792        
Settlement, Expirations or Exercise (4,132) (4,211) (8,347) (8,188)        
Amount Gain/(Loss) Recognized in Income on Derivatives 81 (139) 259 (599)        
Long [Member] | US Treasury Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Amount Gain/(Loss) Recognized in Income on Derivatives (67) 0 (134) 60        
Debt Securities, Trading, and Equity Securities, FV-NI 12,500 3,545 12,500 3,545 12,686 13,458 3,216 1,585
Trading Securities Added During the Period 757 3,968 25,807 9,356        
Notional Amount Of Trading Securities Settlement Expiration During The Period (943) (3,639) (26,765) (7,396)        
Long [Member] | SOFR Futures Contracts                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Amount Gain/(Loss) Recognized in Income on Derivatives   3 (4) 13        
Future [Member] | US Treasury Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (3,747)   (3,747)     (1,396)    
Future [Member] | Short [Member] | US Treasury Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (4,920) (1,964) (4,920) (1,964) (3,210) (3,210) (2,191) (4,373)
Additions 6,629 4,614 9,839 6,805        
Settlement, Expirations or Exercise (4,919) (4,841) (8,129) (9,214)        
Amount Gain/(Loss) Recognized in Income on Derivatives (37) 17 4 (83)        
Future [Member] | Long [Member] | US Treasury Securities [Member]                
Changes in Derivative and Other Hedge Portfolio [Roll Forward]                
Notional Amount (8,667) 0 (8,667) 0 $ (12,455) $ (4,606) $ (668) $ 0
Additions 9,280 600 37,199 1,350        
Settlement, Expirations or Exercise (13,068) (1,268) (33,138) (1,350)        
Amount Gain/(Loss) Recognized in Income on Derivatives $ (79) $ (13) $ (244) $ (13)