v3.25.2
Derivative Instruments - Notional Balances and Fair Values of Derivatives (Detail) - USD ($)
$ in Millions
Mar. 31, 2025
Mar. 31, 2024
Assets    
Gross derivative assets $ 389 $ 743
Collateral posted/held 43 1
Counterparty netting adjustment (429) (701)
Net derivative assets 3 43
Liabilities    
Gross derivative liabilities 1,120 1,472
Collateral posted/held 0 9
Counterparty netting adjustment (429) (701)
Net derivative liabilities 691 780
Interest rate swaps    
Derivatives, Fair Value [Line Items]    
Notional balances 73,058 64,146
Assets    
Gross derivative assets 338 714
Liabilities    
Gross derivative liabilities 676 881
Cross currency swaps    
Derivatives, Fair Value [Line Items]    
Notional balances 8,225 5,755
Assets    
Gross derivative assets 51 29
Liabilities    
Gross derivative liabilities $ 444 $ 591