Allowance for Credit Losses - Allowance for Credit Losses and Finance Receivables by Portfolio Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Abstract]
Provision for credit losses			$ 569	$ 110
Finance Receivables, Net [Member]
Financing Receivable Allowance For Credit Losses [Abstract]
Allowance for credit losses at beginning of period	$ 1,395	$ 1,224	1,272	1,215
Charge-offs	(173)	(64)	(370)	(152)
Recoveries	13	14	42	46
Provision for credit losses	278	45	569	110
Allowance for credit losses at end of period	1,513	1,219	1,513	1,219
Finance Receivables, Net [Member] | Dealer products [Member]
Financing Receivable Allowance For Credit Losses [Abstract]
Allowance for credit losses at beginning of period	74	89	77	140
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	13	(10)	10	(61)
Allowance for credit losses at end of period	87	79	87	79
Finance Receivables, Net [Member] | Retail loan [Member]
Financing Receivable Allowance For Credit Losses [Abstract]
Allowance for credit losses at beginning of period	1,321	1,135	1,195	1,075
Charge-offs	(173)	(64)	(370)	(152)
Recoveries	13	14	42	46
Provision for credit losses	265	55	559	171
Allowance for credit losses at end of period	$ 1,426	$ 1,140	$ 1,426	$ 1,140