Accounts Receivable and Finance Receivables - Summary of impaired finance receivables, excluding leveraged leases, and the average recorded investment (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Summary of impaired finance receivables, excluding leveraged leases, and the average recorded investment
Recorded investment, impaired loans with related allowance for losses	$ 33	$ 55
Recorded investment, impaired loans with no related allowance for losses	41	65
Recorded investment, Total	74	120
Unpaid principal balance	80	125
Allowance for losses on impaired loans	7	11
Average recorded investment	$ 92	$ 101

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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- References

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- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

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- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

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- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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