Related Party Transactions - Related Party Transactions Included in Consolidated Statements of Income (Details) - USD ($) $ in Millions		3 Months Ended
		Jun. 30, 2019	Jun. 30, 2018
Net financing revenues:
Depreciation on operating leases		$ (1,625)	$ (1,766)
Insurance earned premiums and contract revenues:
Insurance premiums and contract revenues		229	224
Expenses:
Operating and administrative expenses		337	324
TMCC-affiliated companies [Member]
Net financing revenues:
Manufacturers’ subvention and other revenues		512	467
Depreciation on operating leases		(10)	(5)
Interest expense:
Credit support fees, interest and other expenses		24	25
Insurance earned premiums and contract revenues:
Insurance premiums and contract revenues		45	45
Investment and other income, net:
Interest and other income		6	2
Expenses:
Operating and administrative expenses		21	23
Insurance losses and loss adjustment expenses	[1]	$ 0	$ (2)

[1] Amount includes the transfer of insurance losses and loss adjustment expenses under a reinsurance contract.