Finance Receivables, Net - Net Financing Receivables (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Mar. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross finance receivables	$ 82,110	$ 80,370
Finance Receivables, Net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross finance receivables	81,981	80,633
Finance Receivables, Net [Member] \| Securitized retail receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross finance receivables	$ 21,900	$ 22,100

Amount, before allowance for credit loss, of financing receivable.

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Name:	us-gaap_NotesReceivableGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant