Variable Interest Entities - Schedule of Assets and Liabilities related to Variable Interest Entities Securitization Transactions (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Variable Interest Entity [Line Items]
Restricted cash	$ 2,251	$ 2,090
Net securitized assets	101,669	90,280
Other assets	4,373	3,921
Debt	122,420	111,685
Other liabilities	6,707	5,674
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash	2,251	2,090
Net securitized assets	31,130	28,764
Other assets	142	108
Debt	34,337	32,736
Other liabilities	66	51
Other assets [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	41,404	39,827
Other assets	142	108
Other liabilities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt	34,337	32,736
Other liabilities	66	51
Retail Finance Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash	1,559	1,434
Retail Finance Receivables [Member] | Other assets [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	31,130	28,764
Other assets	125	85
Retail Finance Receivables [Member] | Other liabilities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt	27,351	25,155
Other liabilities	54	41
Investments In Operating Leases, Net [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash	692	656
Investments In Operating Leases, Net [Member] | Other assets [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net securitized assets	10,274	11,063
Other assets	17	23
Investments In Operating Leases, Net [Member] | Other liabilities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt	6,986	7,581
Other liabilities	$ 12	$ 10