v3.25.4
Fair Value Measurements - Summary of Carrying Values and Fair Values of Financial Instruments Except for those Measured at Fair Value on a Recurring Basis (Detail) - USD ($)
$ in Millions
Dec. 31, 2025
Mar. 31, 2025
Assets    
Dealer loans, net $ 4,494 $ 4,335
Retail loans, net 49,720 48,181
Liabilities    
Commercial paper 4,341 6,022
Related party debt   1,800
Bank loans 2,219 2,100
Public MTN Program 41,365 37,153
Other debt 3,455 3,088
Secured debt 14,433 12,384
Fair value    
Assets    
Dealer loans, net 4,093 3,940
Retail loans, net 50,015 48,102
Liabilities    
Commercial paper 4,341 6,023
Related party debt   1,800
Bank loans 2,224 2,099
Public MTN Program 41,474 36,795
Other debt 3,513 3,130
Secured debt 14,560 12,472
Fair value | Level 1    
Assets    
Dealer loans, net 0 0
Retail loans, net 0 0
Liabilities    
Commercial paper 0 0
Related party debt   0
Bank loans 0 0
Public MTN Program 0 0
Other debt 0 0
Secured debt 0 0
Fair value | Level 2    
Assets    
Dealer loans, net 0 0
Retail loans, net 0 0
Liabilities    
Commercial paper 4,341 6,023
Related party debt   1,800
Bank loans 2,224 2,099
Public MTN Program 41,474 36,795
Other debt 3,513 3,130
Secured debt 14,560 12,472
Fair value | Level 3    
Assets    
Dealer loans, net 4,093 3,940
Retail loans, net 50,015 48,102
Liabilities    
Commercial paper 0 0
Related party debt   0
Bank loans 0 0
Public MTN Program 0 0
Other debt 0 0
Secured debt $ 0 $ 0