Finance Receivables, Net - Aging of Amortized Cost Basis of Finance Receivables by Class (Details) - USD ($) $ in Millions	Dec. 31, 2023	Mar. 31, 2023
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	$ 102,489	$ 91,769
90 Days or greater past due and accruing	187	111
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	1,889	1,270
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	542	378
90 Days or Greater Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	267	179
Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	2,698	1,827
Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	99,791	89,942
Retail Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	86,110	79,646
90 Days or greater past due and accruing	187	111
Retail Loan [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	1,889	1,270
Retail Loan [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	542	378
Retail Loan [Member] | 90 Days or Greater Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	267	179
Retail Loan [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	2,698	1,827
Retail Loan [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	83,412	77,819
Wholesale [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	7,143	3,964
90 Days or greater past due and accruing	0	0
Wholesale [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Wholesale [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Wholesale [Member] | 90 Days or Greater Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Wholesale [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Wholesale [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	7,143	3,964
Real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	4,814	4,975
90 Days or greater past due and accruing	0	0
Real estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Real estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Real estate [Member] | 90 Days or Greater Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Real estate [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Real estate [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	4,814	4,975
Working capital [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	4,422	3,184
90 Days or greater past due and accruing	0	0
Working capital [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Working capital [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Working capital [Member] | 90 Days or Greater Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Working capital [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	0	0
Working capital [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Finance receivables	$ 4,422	$ 3,184