Finance Receivables, Net - Schedule of Amortized Cost Basis of Retail Loan Portfolio and Dealer Products Portfolio by Credit Quality Indicator (Details) - USD ($) $ in Millions	6 Months Ended
	Sep. 30, 2023	Mar. 31, 2023
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	$ 863	$ 2,180
Year two, originated, fiscal year before current fiscal year	1,867	1,349
Year three, originated, two years before current fiscal year	1,209	1,241
Year four, originated, three years before current fiscal year	1,178	264
Year five, originated, four years before current fiscal year	244	424
Originated, more than five years before current fiscal year	1,100	940
Revolving loans	7,442	5,725
Total	13,903	12,123
Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	19,739	32,820
Year two, originated, fiscal year before current fiscal year	27,803	23,222
Year three, originated, two years before current fiscal year	19,195	14,678
Year four, originated, three years before current fiscal year	11,599	5,731
Year five, originated, four years before current fiscal year	4,141	2,279
Originated, more than five years before current fiscal year	1,718	916
Total	84,195	79,646
Gross Charge-Offs, year one, originated, current fiscal year	1
Gross Charge-Offs, Year two, originated, fiscal year before current fiscal year	110
Gross Charge-Offs, Year three, originated, two years before current fiscal year	121
Gross Charge-Offs, Year four, originated, three years before current fiscal year	55
Gross Charge-Offs, Year five, originated, four years before current fiscal year	20
Gross Charge-Offs, Originated, more than five years before current fiscal year	18
Gross Charge-Offs, Total	325
Current [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	19,590	32,377
Year two, originated, fiscal year before current fiscal year	27,113	22,585
Year three, originated, two years before current fiscal year	18,503	14,278
Year four, originated, three years before current fiscal year	11,182	5,555
Year five, originated, four years before current fiscal year	3,980	2,178
Originated, more than five years before current fiscal year	1,587	846
Total	81,955	77,819
30-59 Days Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	110	306
Year two, originated, fiscal year before current fiscal year	480	439
Year three, originated, two years before current fiscal year	487	285
Year four, originated, three years before current fiscal year	298	125
Year five, originated, four years before current fiscal year	114	71
Originated, more than five years before current fiscal year	87	44
Total	1,576	1,270
60-89 Days Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	27	90
Year two, originated, fiscal year before current fiscal year	140	135
Year three, originated, two years before current fiscal year	144	82
Year four, originated, three years before current fiscal year	85	35
Year five, originated, four years before current fiscal year	33	21
Originated, more than five years before current fiscal year	28	15
Total	457	378
90 Days or Greater Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	12	47
Year two, originated, fiscal year before current fiscal year	70	63
Year three, originated, two years before current fiscal year	61	33
Year four, originated, three years before current fiscal year	34	16
Year five, originated, four years before current fiscal year	14	9
Originated, more than five years before current fiscal year	16	11
Total	207	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	5,548	3,964
Total	5,548	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	5,377	3,859
Total	5,377	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	90	54
Total	90	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	79	51
Total	79	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	2	0
Total	2	0
Real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	528	1,391
Year two, originated, fiscal year before current fiscal year	1,207	1,031
Year three, originated, two years before current fiscal year	935	1,059
Year four, originated, three years before current fiscal year	1,018	133
Year five, originated, four years before current fiscal year	131	300
Originated, more than five years before current fiscal year	915	852
Revolving loans	132	209
Total	4,866	4,975
Real estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	527	1,378
Year two, originated, fiscal year before current fiscal year	1,198	1,024
Year three, originated, two years before current fiscal year	922	1,057
Year four, originated, three years before current fiscal year	973	133
Year five, originated, four years before current fiscal year	131	300
Originated, more than five years before current fiscal year	909	850
Revolving loans	132	209
Total	4,792	4,951
Real estate [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	1	5
Year two, originated, fiscal year before current fiscal year	6	0
Year three, originated, two years before current fiscal year	6	2
Year four, originated, three years before current fiscal year	21	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	5	0
Revolving loans	0	0
Total	39	7
Real estate [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	8
Year two, originated, fiscal year before current fiscal year	3	7
Year three, originated, two years before current fiscal year	7	0
Year four, originated, three years before current fiscal year	24	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	1	2
Revolving loans	0	0
Total	35	17
Real estate [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	0	0
Total	0	0
Working capital [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	335	789
Year two, originated, fiscal year before current fiscal year	660	318
Year three, originated, two years before current fiscal year	274	182
Year four, originated, three years before current fiscal year	160	131
Year five, originated, four years before current fiscal year	113	124
Originated, more than five years before current fiscal year	185	88
Revolving loans	1,762	1,552
Total	3,489	3,184
Working capital [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	325	789
Year two, originated, fiscal year before current fiscal year	656	317
Year three, originated, two years before current fiscal year	273	182
Year four, originated, three years before current fiscal year	147	131
Year five, originated, four years before current fiscal year	113	124
Originated, more than five years before current fiscal year	185	88
Revolving loans	1,759	1,552
Total	3,458	3,183
Working capital [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	10	0
Year two, originated, fiscal year before current fiscal year	4	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	3	0
Total	17	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	0	1
Year three, originated, two years before current fiscal year	1	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	14	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	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	0	0
Total	$ 0	$ 0