Financing Receivables - By Portfolio Segment (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($) item	Dec. 31, 2015 USD ($)
Total Lease Receivable and Loan Receivable Portfolio Segments
Financing receivables:
Number of portfolio segments | item	2
Number of classes of financing receivable | item	2
Financing receivables on a gross basis	$ 18,025	$ 19,945
Collectively evaluated for impairment	17,483	19,406
Individually evaluated for impairment	542	539
Allowance for credit losses:
Allowance for credit losses, beginning balance	590	561
Write-offs	(45)	(62)
Provision	72	141
Other	9	(51)
Allowance for credit losses, ending balance	626	590
Collectively evaluated for impairment	113	79
Individually evaluated for impairment	513	511
Total Lease Receivable and Loan Receivable Portfolio Segments | Major Markets
Financing receivables:
Financing receivables on a gross basis	13,858	15,256
Collectively evaluated for impairment	13,781	15,180
Individually evaluated for impairment	77	76
Allowance for credit losses:
Allowance for credit losses, beginning balance	109	111
Write-offs	(19)	(14)
Provision	3	20
Other	4	(8)
Allowance for credit losses, ending balance	97	109
Collectively evaluated for impairment	32	43
Individually evaluated for impairment	64	65
Total Lease Receivable and Loan Receivable Portfolio Segments | Growth Markets
Financing receivables:
Financing receivables on a gross basis	4,167	4,689
Collectively evaluated for impairment	3,703	4,227
Individually evaluated for impairment	464	462
Allowance for credit losses:
Allowance for credit losses, beginning balance	481	450
Write-offs	(26)	(48)
Provision	69	122
Other	5	(43)
Allowance for credit losses, ending balance	529	481
Collectively evaluated for impairment	80	36
Individually evaluated for impairment	449	445
Lease receivables
Financing receivables:
Financing receivables on a gross basis	6,806	7,041
Allowance for credit losses:
Allowance for credit losses, beginning balance	213	165
Allowance for credit losses, ending balance	194	213
Lease receivables | Major Markets
Financing receivables:
Financing receivables on a gross basis	5,180	5,517
Allowance for credit losses:
Allowance for credit losses, beginning balance	25	32
Allowance for credit losses, ending balance	7	25
Lease receivables | Growth Markets
Financing receivables:
Financing receivables on a gross basis	1,626	1,524
Allowance for credit losses:
Allowance for credit losses, beginning balance	188	133
Allowance for credit losses, ending balance	187	188
Loan receivables
Financing receivables:
Financing receivables on a gross basis	11,219	12,904
Allowance for credit losses:
Allowance for credit losses, beginning balance	377	396
Allowance for credit losses, ending balance	432	377
Loan receivables | Major Markets
Financing receivables:
Financing receivables on a gross basis	8,678	9,739
Allowance for credit losses:
Allowance for credit losses, beginning balance	83	79
Allowance for credit losses, ending balance	90	83
Loan receivables | Growth Markets
Financing receivables:
Financing receivables on a gross basis	2,541	3,165
Allowance for credit losses:
Allowance for credit losses, beginning balance	293	317
Allowance for credit losses, ending balance	$ 343	$ 293