Related Party Transactions - Related Party Transactions Included in Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2025	Mar. 31, 2025
Cash and cash equivalents
Cash and cash equivalents	$ 9,128	$ 10,769
Investments in marketable securities
Investments in marketable securities	4,781	4,581
Other assets
Notes receivable	100,301	101,749
Other liabilities
Other payables, net	8,128	7,333
TMCC-affiliated companies [Member]
Finance receivables, net
Accounts receivable	71	73
Deferred retail subvention income	(1,201)	(1,170)
Investments in operating leases, net
Investments in operating leases, net	(84)	(100)
Deferred lease subvention income	(507)	(500)
Other assets
Notes receivable	2,788	2,651
Other receivables, net	89	96
Other liabilities
Unearned voluntary protection contract revenues and insurance earned premiums	485	486
Other payables, net	878	831
Notes payable	92	15
Commercial paper [Member] \| TMCC-affiliated companies [Member]
Investments in marketable securities
Investments in marketable securities	$ 0	$ 15

Amount of deferred operating lease subvention revenue from related parties.

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Amount of deferred retail subvention revenue from related parties.

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The amount of property, by major property class, net of accumulated depreciation, subject to or available for lease as of the balance sheet date.

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Unearned voluntary protection contract revenues and insurance earned premiums.

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Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

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Amount of cash and cash equivalent. Cash includes, but is not limited to, currency on hand, demand deposit with financial institution, and account with general characteristic of demand deposit. Cash equivalent includes, but is not limited to, short-term, highly liquid investment that is both readily convertible to known amount of cash and so near maturity that it presents insignificant risk of change in value because of change in interest rate.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Amount of liabilities classified as other.

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