Financing Receivables - By Portfolio Segment (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($) item	Dec. 31, 2016 USD ($)
Financing receivables
Financing receivables pledged as collateral for borrowings	$ 640	$ 689
Financing receivables held for sale	$ 0	0
Total Lease Receivable and Loan Receivable Portfolio Segments
Financing receivables
Number of portfolio segments | item	2
Number of classes of financing receivable | item	3
Financing receivables on a gross basis	$ 17,631	18,073
Collectively evaluated for impairment	17,358	17,726
Individually evaluated for impairment	273	347
Allowance for credit losses:
Allowance for credit losses, beginning balance	410	590
Write-offs	(112)	(237)
Recoveries	0	2
Provision	16	58
Other	19	(3)
Allowance for credit losses, ending balance	333	410
Collectively evaluated for impairment	85	90
Individually evaluated for impairment	248	320
Total Lease Receivable and Loan Receivable Portfolio Segments | Americas
Financing receivables
Financing receivables on a gross basis	9,721	10,015
Collectively evaluated for impairment	9,581	9,847
Individually evaluated for impairment	140	168
Allowance for credit losses:
Allowance for credit losses, beginning balance	223	175
Write-offs	(49)	(36)
Recoveries	0	2
Provision	11	65
Other	12	17
Allowance for credit losses, ending balance	197	223
Collectively evaluated for impairment	66	62
Individually evaluated for impairment	131	161
Total Lease Receivable and Loan Receivable Portfolio Segments | EMEA
Financing receivables
Financing receivables on a gross basis	4,417	4,480
Collectively evaluated for impairment	4,386	4,460
Individually evaluated for impairment	31	20
Allowance for credit losses:
Allowance for credit losses, beginning balance	22	72
Write-offs	0	(48)
Recoveries	0	0
Provision	9	(1)
Other	5	(1)
Allowance for credit losses, ending balance	36	22
Collectively evaluated for impairment	12	13
Individually evaluated for impairment	23	9
Total Lease Receivable and Loan Receivable Portfolio Segments | Asia Pacific
Financing receivables
Financing receivables on a gross basis	3,493	3,578
Collectively evaluated for impairment	3,391	3,419
Individually evaluated for impairment	102	159
Allowance for credit losses:
Allowance for credit losses, beginning balance	165	343
Write-offs	(63)	(154)
Recoveries	0	0
Provision	(4)	(6)
Other	2	(18)
Allowance for credit losses, ending balance	100	165
Collectively evaluated for impairment	6	15
Individually evaluated for impairment	94	150
Lease receivables
Financing receivables
Financing receivables on a gross basis	6,142	6,336
Allowance for credit losses:
Allowance for credit losses, beginning balance	133	213
Allowance for credit losses, ending balance	118	133
Lease receivables | Americas
Financing receivables
Financing receivables on a gross basis	3,541	3,830
Allowance for credit losses:
Allowance for credit losses, beginning balance	54	52
Allowance for credit losses, ending balance	77	54
Lease receivables | EMEA
Financing receivables
Financing receivables on a gross basis	1,297	1,171
Allowance for credit losses:
Allowance for credit losses, beginning balance	4	17
Allowance for credit losses, ending balance	6	4
Lease receivables | Asia Pacific
Financing receivables
Financing receivables on a gross basis	1,304	1,335
Allowance for credit losses:
Allowance for credit losses, beginning balance	76	143
Allowance for credit losses, ending balance	35	76
Loan receivables
Financing receivables
Financing receivables on a gross basis	11,489	11,737
Allowance for credit losses:
Allowance for credit losses, beginning balance	276	377
Allowance for credit losses, ending balance	215	276
Loan receivables | Americas
Financing receivables
Financing receivables on a gross basis	6,180	6,185
Allowance for credit losses:
Allowance for credit losses, beginning balance	169	122
Allowance for credit losses, ending balance	120	169
Loan receivables | EMEA
Financing receivables
Financing receivables on a gross basis	3,120	3,309
Allowance for credit losses:
Allowance for credit losses, beginning balance	18	55
Allowance for credit losses, ending balance	29	18
Loan receivables | Asia Pacific
Financing receivables
Financing receivables on a gross basis	2,189	2,243
Allowance for credit losses:
Allowance for credit losses, beginning balance	89	200
Allowance for credit losses, ending balance	$ 65	$ 89