Finance Receivables - Allowance for Loan Losses (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses	$ 59	$ 327	$ 33	$ 793
Retail Finance Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for retail loan losses beginning balance	1,784	1,879	1,915	866
Provision for loan losses	67	332	54	788
Charge-offs	(204)	(256)	(457)	(596)
Recoveries	144	89	293	245
Foreign currency translation	14	0	0	(60)
Allowance for retail loan losses ending balance	1,805	2,044	1,805	2,044
Retail Finance Receivables \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for retail loan losses beginning balance	$ 0	$ 0	$ 0	$ 801

Amount of foreign currency translation gain (loss) which (increases) decreases allowance for credit loss on financing receivable.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of credit loss expense (reversal of expense) for financing receivable.

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