v3.26.1
Derivative Instruments (Fair Value Hedge Attributable to Foreign Currency) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Interest Rate Contract | Income Statement Location [Axis]: us-gaap:BenefitsLossesAndExpenses        
Derivative Instruments, Gain (Loss) [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments $ 0 $ 0 $ 0 $ 0
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge 0 0 0 0
Interest Rate Contract | Income Statement Location [Axis]: us-gaap:InterestExpenseBorrowings        
Derivative Instruments, Gain (Loss) [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments (17) 2 (25) 22
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge 18 (1) 27 (26)
Financial Futures | Income Statement Location [Axis]: us-gaap:BenefitsLossesAndExpenses        
Derivative Instruments, Gain (Loss) [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments (8) 1 (10) 14
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge 7 (1) 11 (14)
Financial Futures | Income Statement Location [Axis]: us-gaap:InterestExpenseBorrowings        
Derivative Instruments, Gain (Loss) [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments 0 0 0 0
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge $ 0 $ 0 $ 0 $ 0