v3.25.2
Derivative Instruments - Notional Balances and Fair Values of Derivatives (Detail) - USD ($)
$ in Millions
Jun. 30, 2025
Mar. 31, 2025
Derivatives, Fair Value [Line Items]    
Assets $ 926 $ 389
Collateral posted/held 32 43
Counterparty netting adjustment (608) (429)
Net derivative assets 350 3
Liabilities 782 1,120
Collateral posted/held 0 0
Counterparty netting adjustment (608) (429)
Net derivative liabilities 174 691
Interest rate swaps    
Derivatives, Fair Value [Line Items]    
Notional balances 75,174 73,058
Assets 368 338
Liabilities 616 676
Cross currency swaps    
Derivatives, Fair Value [Line Items]    
Notional balances 10,408 8,225
Assets 558 51
Liabilities $ 166 $ 444