Fair Value Measurements - Assets and Liabilities Not Carried at Fair Value on Recurring Basis on Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Mar. 31, 2023	Mar. 31, 2022
Carrying value [Member] | Unsecured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	$ 78,949	$ 82,288
Carrying value [Member] | Secured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	32,736	26,864
Fair value [Member] | Unsecured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	76,401	80,980
Fair value [Member] | Secured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	32,173	26,500
Fair value [Member] | Level 1 [Member] | Unsecured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	0	0
Fair value [Member] | Level 1 [Member] | Secured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	0	0
Fair value [Member] | Level 2 [Member] | Unsecured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	76,401	80,980
Fair value [Member] | Level 2 [Member] | Secured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	0	0
Fair value [Member] | Level 3 [Member] | Unsecured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	0	0
Fair value [Member] | Level 3 [Member] | Secured Notes and Loans Payable [Member]
Financial liabilities
Financial liabilities	32,173	26,500
Retail Loan [Member] | Carrying value [Member]
Financial assets
Finance receivables, net	78,445	72,369
Retail Loan [Member] | Fair value [Member]
Financial assets
Finance receivables, net	77,649	73,385
Retail Loan [Member] | Fair value [Member] | Level 1 [Member]
Financial assets
Finance receivables, net	0	0
Retail Loan [Member] | Fair value [Member] | Level 2 [Member]
Financial assets
Finance receivables, net	0	0
Retail Loan [Member] | Fair value [Member] | Level 3 [Member]
Financial assets
Finance receivables, net	77,649	73,385
Wholesale [Member] | Carrying value [Member]
Financial assets
Finance receivables, net	3,972	2,940
Wholesale [Member] | Fair value [Member]
Financial assets
Finance receivables, net	3,968	2,931
Wholesale [Member] | Fair value [Member] | Level 1 [Member]
Financial assets
Finance receivables, net	0	0
Wholesale [Member] | Fair value [Member] | Level 2 [Member]
Financial assets
Finance receivables, net	0	0
Wholesale [Member] | Fair value [Member] | Level 3 [Member]
Financial assets
Finance receivables, net	3,968	2,931
Real estate [Member] | Carrying value [Member]
Financial assets
Finance receivables, net	4,981	4,985
Real estate [Member] | Fair value [Member]
Financial assets
Finance receivables, net	4,990	4,961
Real estate [Member] | Fair value [Member] | Level 1 [Member]
Financial assets
Finance receivables, net	0	0
Real estate [Member] | Fair value [Member] | Level 2 [Member]
Financial assets
Finance receivables, net	0	0
Real estate [Member] | Fair value [Member] | Level 3 [Member]
Financial assets
Finance receivables, net	4,990	4,961
Working capital [Member] | Carrying value [Member]
Financial assets
Finance receivables, net	3,113	2,256
Working capital [Member] | Fair value [Member]
Financial assets
Finance receivables, net	3,058	2,171
Working capital [Member] | Fair value [Member] | Level 1 [Member]
Financial assets
Finance receivables, net	0	0
Working capital [Member] | Fair value [Member] | Level 2 [Member]
Financial assets
Finance receivables, net	0	0
Working capital [Member] | Fair value [Member] | Level 3 [Member]
Financial assets
Finance receivables, net	$ 3,058	$ 2,171