Related Party Transactions - Related Party Transactions Included in Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Cash and cash equivalents
Cash and cash equivalents	$ 8,570	$ 6,398
Other assets
Notes receivable	101,669	90,280
Other liabilities
Other payables, net	6,707	5,674
TMCC-affiliated companies [Member]
Finance receivables, net
Accounts receivable	49	47
Deferred retail subvention income	(953)	(922)
Investments in operating leases, net
Investments in operating leases, net	(80)	(250)
Deferred lease subvention income	(323)	(410)
Other assets
Notes receivable	1,724	1,237
Other receivables, net	86	89
Other liabilities
Unearned voluntary protection contract revenues and insurance earned premiums	433	399
Other payables, net	771	432
Notes payable	8	8
Commercial paper [Member] | TMCC-affiliated companies [Member]
Cash and cash equivalents
Cash and cash equivalents	$ 0	$ 35