Finance Receivables, Net - Schedule of Amortized Cost Basis of Retail Loan Portfolio and Dealer Products Portfolio by Credit Quality Indicator (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	$ 2,083	$ 2,180
Year two, originated, fiscal year before current fiscal year	1,381	1,349
Year three, originated, two years before current fiscal year	1,117	1,241
Year four, originated, three years before current fiscal year	1,026	264
Year five, originated, four years before current fiscal year	235	424
Originated, more than five years before current fiscal year	945	940
Revolving loans	9,394	5,725
Total	16,181	12,123
Gross Charges Off, Total	0
Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	35,823	32,820
Year two, originated, fiscal year before current fiscal year	23,173	23,222
Year three, originated, two years before current fiscal year	15,639	14,678
Year four, originated, three years before current fiscal year	8,878	5,731
Year five, originated, four years before current fiscal year	2,783	2,279
Originated, more than five years before current fiscal year	829	916
Total	87,125	79,646
Gross Charge-Offs, year one, originated, current fiscal year	38
Gross Charge-Offs, Year two, originated, fiscal year before current fiscal year	297
Gross Charge-Offs, Year three, originated, two years before current fiscal year	258
Gross Charge-Offs, Year four, originated, three years before current fiscal year	111
Gross Charge-Offs, Year five, originated, four years before current fiscal year	38
Gross Charge-Offs, Originated, more than five years before current fiscal year	34
Gross Charges Off, Total	776
Current [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	35,407	32,377
Year two, originated, fiscal year before current fiscal year	22,473	22,585
Year three, originated, two years before current fiscal year	15,041	14,278
Year four, originated, three years before current fiscal year	8,539	5,555
Year five, originated, four years before current fiscal year	2,654	2,178
Originated, more than five years before current fiscal year	748	846
Total	84,862	77,819
30-59 Days Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	301	306
Year two, originated, fiscal year before current fiscal year	488	439
Year three, originated, two years before current fiscal year	426	285
Year four, originated, three years before current fiscal year	242	125
Year five, originated, four years before current fiscal year	92	71
Originated, more than five years before current fiscal year	53	44
Total	1,602	1,270
60-89 Days Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	77	90
Year two, originated, fiscal year before current fiscal year	143	135
Year three, originated, two years before current fiscal year	119	82
Year four, originated, three years before current fiscal year	68	35
Year five, originated, four years before current fiscal year	27	21
Originated, more than five years before current fiscal year	17	15
Total	451	378
90 Days or Greater Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	38	47
Year two, originated, fiscal year before current fiscal year	69	63
Year three, originated, two years before current fiscal year	53	33
Year four, originated, three years before current fiscal year	29	16
Year five, originated, four years before current fiscal year	10	9
Originated, more than five years before current fiscal year	11	11
Total	210	179
Wholesale [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	6,673	3,964
Total	6,673	3,964
Wholesale [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	6,287	3,859
Total	6,287	3,859
Wholesale [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	238	54
Total	238	54
Wholesale [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	112	51
Total	112	51
Wholesale [Member] | Default [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	36	0
Total	36	0
Real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	1,294	1,391
Year two, originated, fiscal year before current fiscal year	923	1,031
Year three, originated, two years before current fiscal year	869	1,059
Year four, originated, three years before current fiscal year	891	133
Year five, originated, four years before current fiscal year	128	300
Originated, more than five years before current fiscal year	786	852
Revolving loans	3	209
Total	4,894	4,975
Real estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	1,224	1,378
Year two, originated, fiscal year before current fiscal year	883	1,024
Year three, originated, two years before current fiscal year	815	1,057
Year four, originated, three years before current fiscal year	860	133
Year five, originated, four years before current fiscal year	128	300
Originated, more than five years before current fiscal year	784	850
Revolving loans	3	209
Total	4,697	4,951
Real estate [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	58	5
Year two, originated, fiscal year before current fiscal year	37	0
Year three, originated, two years before current fiscal year	44	2
Year four, originated, three years before current fiscal year	6	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	0	0
Total	145	7
Real estate [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	8	8
Year two, originated, fiscal year before current fiscal year	1	7
Year three, originated, two years before current fiscal year	10	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	2	2
Revolving loans	0	0
Total	21	17
Real estate [Member] | Default [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	4	0
Year two, originated, fiscal year before current fiscal year	2	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	25	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	0	0
Total	31	0
Working capital [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	789	789
Year two, originated, fiscal year before current fiscal year	458	318
Year three, originated, two years before current fiscal year	248	182
Year four, originated, three years before current fiscal year	135	131
Year five, originated, four years before current fiscal year	107	124
Originated, more than five years before current fiscal year	159	88
Revolving loans	2,718	1,552
Total	4,614	3,184
Working capital [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	769	789
Year two, originated, fiscal year before current fiscal year	414	317
Year three, originated, two years before current fiscal year	235	182
Year four, originated, three years before current fiscal year	122	131
Year five, originated, four years before current fiscal year	105	124
Originated, more than five years before current fiscal year	159	88
Revolving loans	2,715	1,552
Total	4,519	3,183
Working capital [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	20	0
Year two, originated, fiscal year before current fiscal year	41	0
Year three, originated, two years before current fiscal year	13	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	2	0
Total	76	0
Working capital [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	3	1
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	2	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	1	0
Total	6	1
Working capital [Member] | Default [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	13	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	0	0
Total	$ 13	$ 0