Variable Interest Entities - Schedule of Assets and Liabilities related to Variable Interest Entities Securitization Transactions (Details) - USD ($) $ in Millions	Dec. 31, 2021	Mar. 31, 2021
Variable Interest Entity [Line Items]
Restricted cash	$ 2,372	$ 1,957
Net securitized assets	80,925	79,192
Other assets	2,450	2,473
Debt	110,122	109,725
Other liabilities	5,725	5,548
Other assets [Member]
Variable Interest Entity [Line Items]
Restricted cash	1,849	1,957
Net securitized assets	34,071	28,344
Other assets	73	89
Other liabilities [Member]
Variable Interest Entity [Line Items]
Debt	28,068	24,212
Other liabilities	10	14
Retail Finance Receivables [Member] | Other assets [Member]
Variable Interest Entity [Line Items]
Restricted cash	1,233	1,521
Net securitized assets	21,637	21,745
Other assets	51	46
Retail Finance Receivables [Member] | Other liabilities [Member]
Variable Interest Entity [Line Items]
Debt	19,230	19,665
Other liabilities	8	13
Investments In Operating Leases, Net [Member] | Other assets [Member]
Variable Interest Entity [Line Items]
Restricted cash	616	436
Net securitized assets	12,434	6,599
Other assets	22	43
Investments In Operating Leases, Net [Member] | Other liabilities [Member]
Variable Interest Entity [Line Items]
Debt	8,838	4,547
Other liabilities	$ 2	$ 1