v3.26.1
Derivative and Other Hedging Instruments (US Treasury Securities) (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Derivative [Line Items]            
U.S. Treasury securities, net $ (5,825)   $ (2,975)      
At Par Value [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (5,870)   (2,920)      
US Treasury Securities [Member] | Future [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 3,747   1,396      
Derivative, Forward Settlement Value 3,792   1,457      
Derivative Asset, Fair Value, Gross Asset 3,725   1,468      
Derivative, Fair Value, Net (67)   11      
TBA and Forward Settling Agency Securities [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 10,047 $ 10,909 13,180 $ 8,407 $ 7,811 $ 6,955
Derivative, Forward Settlement Value 9,676   12,917      
Derivative Asset, Fair Value, Gross Asset 9,728   12,988      
Derivative, Fair Value, Net 52   71      
Less Than or Equal to Five Years            
Derivative [Line Items]            
U.S. Treasury securities, net 9,556   12,470      
Greater Than Five Years and Less than or Equal to Seven Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net 81   (838)      
Greater Than Seven Years and Less than or Equal to Ten Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (13,345)   (12,390)      
Greater Than Ten Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (2,162)   (2,162)      
5 Year Maturity [Member] | US Treasury Securities [Member]            
Derivative [Line Items]            
Derivative, Fair Value, Net (2)   0      
Greater Than Ten Years [Member] | US Treasury Securities [Member] | Future [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 3,210   3,210      
Derivative, Forward Settlement Value 3,558   3,718      
Derivative Asset, Fair Value, Gross Asset 3,643   3,710      
Derivative, Fair Value, Net (85)   8      
Greater Than Five Years and Less than or Equal to Seven Years [Member] | US Treasury Securities [Member] | Future [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 5,254   4,606      
Derivative, Forward Settlement Value 5,731   5,175      
Derivative Asset, Fair Value, Gross Asset 5,774   5,178      
Derivative, Fair Value, Net 43   3      
Greater Than Seven Years and Less than or Equal to Ten Years [Member] | US Treasury Securities [Member] | Future [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 1,710   0      
Derivative, Forward Settlement Value 1,900   0      
Derivative Asset, Fair Value, Gross Asset 1,923   0      
Derivative, Fair Value, Net $ (23)   $ 0      
Short [Member] | US Treasury Securities [Member]            
Derivative [Line Items]            
Weighted Average Yield Percentage 4.28%   4.21%      
Short [Member] | US Treasury Securities [Member]            
Derivative [Line Items]            
Derivative, Notional Amount $ 18,370 17,162 $ 16,378 21,396 17,636 17,792
Short [Member] | US Treasury Securities [Member] | Future [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 4,920 3,210 3,210 1,964 2,191 4,373
Derivative Asset, Fair Value, Gross Asset 5,600   3,700      
Short [Member] | 5 Year Maturity [Member] | US Treasury Securities [Member]            
Derivative [Line Items]            
Derivative, Notional Amount 3,413   0      
Derivative, Forward Settlement Value 3,519   0      
Derivative Asset, Fair Value, Gross Asset $ 3,517   $ 0      
Long [Member] | US Treasury Securities [Member]            
Derivative [Line Items]            
Weighted Average Yield Percentage 3.71%   3.67%      
Long [Member] | US Treasury Securities [Member] | Future [Member]            
Derivative [Line Items]            
Derivative, Notional Amount $ 8,667 $ 12,455 $ 4,606 $ 0 $ 668 $ 0
Derivative Asset, Fair Value, Gross Asset 9,300   5,200      
Fair Value Hedging [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (5,825)   (2,975)      
Fair Value Hedging [Member] | Less Than or Equal to Five Years            
Derivative [Line Items]            
U.S. Treasury securities, net 9,418   12,467      
Fair Value Hedging [Member] | Greater Than Five Years and Less than or Equal to Seven Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net 81   (774)      
Fair Value Hedging [Member] | Greater Than Seven Years and Less than or Equal to Ten Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (13,185)   (12,493)      
Fair Value Hedging [Member] | Greater Than Ten Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (2,139)   (2,175)      
Fair Value Hedging [Member] | Short [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net 18,200   16,500      
Fair Value Hedging [Member] | Long [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net 12,300   13,500      
At Cost Basis [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (5,885)   (2,913)      
At Cost Basis [Member] | Less Than or Equal to Five Years            
Derivative [Line Items]            
U.S. Treasury securities, net 9,502   12,465      
At Cost Basis [Member] | Greater Than Five Years and Less than or Equal to Seven Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net 81   (834)      
At Cost Basis [Member] | Greater Than Seven Years and Less than or Equal to Ten Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net (13,259)   (12,334)      
At Cost Basis [Member] | Greater Than Ten Years [Member]            
Derivative [Line Items]            
U.S. Treasury securities, net $ (2,209)   $ (2,210)