Segment Information - Schedule of Segment Reporting Information by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022
Segment Reporting Information [Line Items]
Total financing revenues	$ 2,831	$ 2,999
Depreciation on operating leases	1,409	1,441
Interest expense	563	286
Net financing revenues	859	1,272
Voluntary protection contract revenues and insurance earned premiums	259	249
Investment and other income (loss), net	(306)	156
Net financing revenues and other revenues	812	1,677
Expenses:
Provision for credit losses	78	(3)
Operating and administrative	406	384
Voluntary protection contract expenses and insurance losses	107	108
Total expenses	591	489
Income before income taxes	221	1,188
Provision for income taxes	51	267
Net income	170	921
Total assets	136,132	134,401	$ 135,041
Intercompany Eliminations [Member]
Segment Reporting Information [Line Items]
Total financing revenues	0	0
Depreciation on operating leases	0	0
Interest expense	0	0
Net financing revenues	0	0
Voluntary protection contract revenues and insurance earned premiums	0	0
Investment and other income (loss), net	0	0
Net financing revenues and other revenues	0	0
Expenses:
Provision for credit losses	0	0
Operating and administrative	0	0
Voluntary protection contract expenses and insurance losses	0	0
Total expenses	0	0
Income before income taxes	0	0
Provision for income taxes	0	0
Net income	0	0
Total assets	(135)	(138)
Finance Operations [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total financing revenues	2,831	2,999
Depreciation on operating leases	1,409	1,441
Interest expense	563	286
Net financing revenues	859	1,272
Voluntary protection contract revenues and insurance earned premiums	0	0
Investment and other income (loss), net	33	19
Net financing revenues and other revenues	892	1,291
Expenses:
Provision for credit losses	78	(3)
Operating and administrative	299	292
Voluntary protection contract expenses and insurance losses	0	0
Total expenses	377	289
Income before income taxes	515	1,002
Provision for income taxes	125	221
Net income	390	781
Total assets	130,054	128,015
Voluntary Protection Operations [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total financing revenues	0	0
Depreciation on operating leases	0	0
Interest expense	0	0
Net financing revenues	0	0
Voluntary protection contract revenues and insurance earned premiums	259	249
Investment and other income (loss), net	(339)	137
Net financing revenues and other revenues	(80)	386
Expenses:
Provision for credit losses	0	0
Operating and administrative	107	92
Voluntary protection contract expenses and insurance losses	107	108
Total expenses	214	200
Income before income taxes	(294)	186
Provision for income taxes	(74)	46
Net income	(220)	140
Total assets	$ 6,213	$ 6,524