Variable Interest Entities - Schedule of Assets and Liabilities related to Variable Interest Entities Securitization Transactions (Details) - USD ($) $ in Millions	Mar. 31, 2025	Mar. 31, 2024
Variable Interest Entity [Line Items]
Restricted cash and cash equivalents	$ 2,490	$ 2,251
Net securitized assets	101,749	101,669
Other assets	5,615	4,373
Debt	127,745	122,420
Other liabilities	7,333	6,707
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	33,958	31,130
Other assets	167	142
Debt	37,717	34,337
Other liabilities	72	66
Other assets [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	44,680	41,404
Other assets	167	142
Other liabilities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt	37,717	34,337
Other liabilities	72	66
Retail Finance Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash and cash equivalents	1,853	1,559
Retail Finance Receivables [Member] | Other assets [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	33,958	31,130
Other assets	152	125
Retail Finance Receivables [Member] | Other liabilities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt	30,448	27,351
Other liabilities	62	54
Investments In Operating Leases, Net [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash and cash equivalents	637	692
Investments In Operating Leases, Net [Member] | Other assets [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	10,722	10,274
Other assets	15	17
Investments In Operating Leases, Net [Member] | Other liabilities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt	7,269	6,986
Other liabilities	$ 10	$ 12