Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Allowance for credit losses, finance receivables
Beginning balance	$ 600	$ 517	$ 597	$ 484
Charge-offs	(124)	(112)	(257)	(237)
Recoveries	48	38	88	72
Provision for credit losses	70	73	164	194
Other	(7)	6	(5)	9
Ending balance	587	522	587	522
Analysis of ending balance of allowance for credit losses, finance receivables
Collective impairment allowance	565	500	565	500
Specific impairment allowance	22	22	22	22
Ending balance	587	522	587	522
Analysis of ending balance of finance receivables
Collectively evaluated for impairment	116,006	108,260	116,006	108,260
Specifically evaluated for impairment	474	562	474	562
Financing Receivables	116,480	108,822	116,480	108,822	$ 116,600
Allowance for credit losses, net investment in operating leases
Beginning balance	71	67	71	64
Charge-offs	(47)	(52)	(98)	(104)
Recoveries	26	25	52	49
Other	0	0	0	0
Ending balance	72	66	72	66
Analysis of ending balance of allowance for credit losses, net investment in operating leases
Collective impairment allowance	72	66	72	66
Specific impairment allowance	0	0	0	0
Ending balance	72	66	72	66
Analysis of ending balance of net investment in operating leases
Collectively evaluated for impairment	27,386	26,759	27,386	26,759
Individually evaluated for impairment	0	0	0	0
Net investment in operating leases before allowance for credit losses	27,386	26,759	27,386	26,759	26,732
Total allowance
Beginning balance	671	584	668	548
Charge-offs	(171)	(164)	(355)	(341)
Recoveries	74	63	140	121
Provision for credit losses	92	99	211	251
Other	(7)	6	(5)	9
Ending balance	659	588	659	588
Analysis of Ending Balance of Finance Receivables and Net Investment in Operating Leases [Abstract]
Collective impairment allowance	637	566	637	566
Specific impairment allowance	22	22	22	22
Ending balance	659	588	659	588
Ending balance, net of allowance for credit losses	115,893	108,300	115,893	108,300	116,003
Ending balance, net investment in operating leases	27,314	26,693	27,314	26,693	26,661
Net Investment in Operating Leases [Member]
Allowance for credit losses, finance receivables
Provision for credit losses	22	26	47	57
Consumer Segment [Member]
Allowance for credit losses, finance receivables
Beginning balance	584	504	582	469
Charge-offs	(123)	(110)	(254)	(233)
Recoveries	47	35	86	69
Provision for credit losses	72	73	164	194
Other	(7)	5	(5)	8
Ending balance	573	507	573	507
Analysis of ending balance of allowance for credit losses, finance receivables
Collective impairment allowance	552	487	552	487
Specific impairment allowance	21	20	21	20
Ending balance	573	507	573	507
Analysis of ending balance of finance receivables
Collectively evaluated for impairment	75,338	67,906	75,338	67,906
Specifically evaluated for impairment	378	381	378	381
Financing Receivables	75,716	68,287	75,716	68,287	75,187
Analysis of Ending Balance of Finance Receivables and Net Investment in Operating Leases [Abstract]
Ending balance, net of allowance for credit losses	75,143	67,780	75,143	67,780
Non-Consumer Segment [Member]
Allowance for credit losses, finance receivables
Beginning balance	16	13	15	15
Charge-offs	(1)	(2)	(3)	(4)
Recoveries	1	3	2	3
Provision for credit losses	(2)	0	0	0
Other	0	1	0	1
Ending balance	14	15	14	15
Analysis of ending balance of allowance for credit losses, finance receivables
Collective impairment allowance	13	13	13	13
Specific impairment allowance	1	2	1	2
Ending balance	14	15	14	15
Analysis of ending balance of finance receivables
Collectively evaluated for impairment	40,668	40,354	40,668	40,354
Specifically evaluated for impairment	96	181	96	181
Financing Receivables	40,764	40,535	40,764	40,535	$ 41,413
Analysis of Ending Balance of Finance Receivables and Net Investment in Operating Leases [Abstract]
Ending balance, net of allowance for credit losses	$ 40,750	$ 40,520	$ 40,750	$ 40,520