Finance Receivables - Allowance for Loan Losses (Details) - Retail Finance Receivables [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for retail loan losses beginning balance	$ 1,879	$ 862	$ 866	$ 844
Provision for loan losses	332	165	788	343
Charge-offs	(256)	(279)	(596)	(586)
Recoveries	89	132	245	277
Foreign currency translation	0	1	(60)	3
Allowance for retail loan losses ending balance	$ 2,044	$ 881	2,044	$ 881
Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for retail loan losses beginning balance			$ 801

Amount of gain (loss) from converting allowance reserve for credit loss to currency of reporting entity from amount denominated or measured in a different currency, which decreases (increases) the allowance for loan and lease losses.

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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 expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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