Finance Receivables, Net - Schedule of Amortized Cost Basis of Retail Loan Portfolio and Dealer Products Portfolio by Credit Quality Indicator (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2025	Mar. 31, 2025
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	$ 2,703	$ 2,703	$ 2,639
Year two, originated, fiscal year before current fiscal year	1,528	1,528	1,259
Year three, originated, two years before current fiscal year	843	843	711
Year four, originated, three years before current fiscal year	525	525	747
Year five, originated, four years before current fiscal year	645	645	880
Originated, more than five years before current fiscal year	1,237	1,237	810
Revolving loans	11,167	11,167	9,475
Total	18,648	18,648	16,521
Gross Charge-Offs, Total	0	0	0
Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	23,718	23,718	32,328
Year two, originated, fiscal year before current fiscal year	24,881	24,881	24,770
Year three, originated, two years before current fiscal year	17,491	17,491	14,941
Year four, originated, three years before current fiscal year	9,896	9,896	9,505
Year five, originated, four years before current fiscal year	5,838	5,838	4,300
Originated, more than five years before current fiscal year	2,196	2,196	1,028
Total	84,020	84,020	86,872
Gross Charge-Offs, year one, originated, current fiscal year		9	31
Gross Charge-Offs, Year two, originated, fiscal year before current fiscal year		151	254
Gross Charge-Offs, Year three, originated, two years before current fiscal year		186	304
Gross Charge-Offs, Year four, originated, three years before current fiscal year		157	188
Gross Charge-Offs, Year five, originated, four years before current fiscal year		84	72
Gross Charge-Offs, Originated, more than five years before current fiscal year		41	38
Gross Charge-Offs, Total		628	887
Current [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	23,519	23,519	32,049
Year two, originated, fiscal year before current fiscal year	24,401	24,401	24,235
Year three, originated, two years before current fiscal year	16,947	16,947	14,395
Year four, originated, three years before current fiscal year	9,423	9,423	9,095
Year five, originated, four years before current fiscal year	5,500	5,500	4,094
Originated, more than five years before current fiscal year	2,009	2,009	941
Total	81,799	81,799	84,809
30-59 Days Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	137	137	198
Year two, originated, fiscal year before current fiscal year	321	321	377
Year three, originated, two years before current fiscal year	368	368	384
Year four, originated, three years before current fiscal year	317	317	295
Year five, originated, four years before current fiscal year	231	231	147
Originated, more than five years before current fiscal year	124	124	57
Total	1,498	1,498	1,458
60-89 Days Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	42	42	57
Year two, originated, fiscal year before current fiscal year	106	106	110
Year three, originated, two years before current fiscal year	122	122	112
Year four, originated, three years before current fiscal year	108	108	80
Year five, originated, four years before current fiscal year	74	74	41
Originated, more than five years before current fiscal year	41	41	18
Total	493	493	418
90 Days or Greater Past Due [Member] | Retail Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	20	20	24
Year two, originated, fiscal year before current fiscal year	53	53	48
Year three, originated, two years before current fiscal year	54	54	50
Year four, originated, three years before current fiscal year	48	48	35
Year five, originated, four years before current fiscal year	33	33	18
Originated, more than five years before current fiscal year	22	22	12
Total	230	230	187
Wholesale [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	0	0	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	0	0	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	7,294	7,294	6,498
Total	7,294	7,294	6,498
Wholesale [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	0	0	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	0	0	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	6,947	6,947	6,042
Total	6,947	6,947	6,042
Wholesale [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	0	0	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	0	0	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	258	258	408
Total	258	258	408
Wholesale [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	0	0	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	0	0	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	46	46	40
Total	46	46	40
Wholesale [Member] | Default [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	0	0	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	0	0	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	43	43	8
Total	43	43	8
Real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	1,959	1,959	1,814
Year two, originated, fiscal year before current fiscal year	1,060	1,060	790
Year three, originated, two years before current fiscal year	563	563	493
Year four, originated, three years before current fiscal year	384	384	592
Year five, originated, four years before current fiscal year	516	516	775
Originated, more than five years before current fiscal year	995	995	628
Revolving loans	421	421	92
Total	5,898	5,898	5,184
Real estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	1,908	1,908	1,755
Year two, originated, fiscal year before current fiscal year	1,026	1,026	691
Year three, originated, two years before current fiscal year	492	492	485
Year four, originated, three years before current fiscal year	373	373	568
Year five, originated, four years before current fiscal year	483	483	773
Originated, more than five years before current fiscal year	964	964	596
Revolving loans	421	421	92
Total	5,667	5,667	4,960
Real estate [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	39	39	55
Year two, originated, fiscal year before current fiscal year	23	23	89
Year three, originated, two years before current fiscal year	19	19	8
Year four, originated, three years before current fiscal year	0	0	22
Year five, originated, four years before current fiscal year	7	7	2
Originated, more than five years before current fiscal year	2	2	32
Revolving loans	0	0	0
Total	90	90	208
Real estate [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	8	8	0
Year two, originated, fiscal year before current fiscal year	0	0	10
Year three, originated, two years before current fiscal year	10	10	0
Year four, originated, three years before current fiscal year	0	0	2
Year five, originated, four years before current fiscal year	2	2	0
Originated, more than five years before current fiscal year	12	12	0
Revolving loans	0	0	0
Total	32	32	12
Real estate [Member] | Default [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	4	4	4
Year two, originated, fiscal year before current fiscal year	11	11	0
Year three, originated, two years before current fiscal year	42	42	0
Year four, originated, three years before current fiscal year	11	11	0
Year five, originated, four years before current fiscal year	24	24	0
Originated, more than five years before current fiscal year	17	17	0
Revolving loans	0	0	0
Total	109	109	4
Working capital [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	744	744	825
Year two, originated, fiscal year before current fiscal year	468	468	469
Year three, originated, two years before current fiscal year	280	280	218
Year four, originated, three years before current fiscal year	141	141	155
Year five, originated, four years before current fiscal year	129	129	105
Originated, more than five years before current fiscal year	242	242	182
Revolving loans	3,452	3,452	2,885
Total	5,456	5,456	4,839
Working capital [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	725	725	775
Year two, originated, fiscal year before current fiscal year	443	443	420
Year three, originated, two years before current fiscal year	250	250	204
Year four, originated, three years before current fiscal year	140	140	152
Year five, originated, four years before current fiscal year	125	125	105
Originated, more than five years before current fiscal year	242	242	181
Revolving loans	3,442	3,442	2,789
Total	5,367	5,367	4,626
Working capital [Member] | Credit Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	19	19	50
Year two, originated, fiscal year before current fiscal year	23	23	49
Year three, originated, two years before current fiscal year	30	30	14
Year four, originated, three years before current fiscal year	1	1	3
Year five, originated, four years before current fiscal year	1	1	0
Originated, more than five years before current fiscal year	0	0	1
Revolving loans	4	4	92
Total	78	78	209
Working capital [Member] | At Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	2	2	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	0	0	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	3	3	4
Total	5	5	4
Working capital [Member] | Default [Member]
Financing Receivable, Recorded Investment [Line Items]
Year one, originated, current fiscal year	0	0	0
Year two, originated, fiscal year before current fiscal year	0	0	0
Year three, originated, two years before current fiscal year	0	0	0
Year four, originated, three years before current fiscal year	0	0	0
Year five, originated, four years before current fiscal year	3	3	0
Originated, more than five years before current fiscal year	0	0	0
Revolving loans	3	3	0
Total	$ 6	$ 6	$ 0