Finance Receivables - Aging Analysis (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold Period For Past Due Finance Receivables	31 days
Finance Receivables Aging Analysis [Abstract]
Financing Receivables	$ 119,403	$ 116,600
Consumer Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	20	24
Finance Receivables Aging Analysis [Abstract]
Total past due	1,060	934
Current	75,179	74,253
Financing Receivables	76,239	75,187
Non-Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	76	122
Current	43,088	41,291
Financing Receivables	43,164	41,413
31-60 Days Past Due [Member] \| Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	859	748
61-90 Days Past Due [Member] \| Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	123	113
91-120 Days Past Due [Member] \| Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	39	36
Greater Than 120 Days Past Due [Member] \| Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	$ 39	$ 37

Finance Receivables Aging Analysis [Abstract]

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Threshold Period For Past Due Finance Receivables

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Recorded investment in financing receivables that are 90 days or more past due and still accruing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

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Financing receivables that are current.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524

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Recorded Investment in financing receivables that are past due at the balance sheet date.

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Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(3))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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