Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Allowance for credit losses, finance receivables
Beginning balance	$ 597	$ 484
Charge-offs	(133)	(125)
Recoveries	40	34
Provision for credit losses	94	121
Other	2	3
Ending balance	600	517
Analysis of ending balance of allowance for credit losses, finance receivables
Collective impairment allowance	578	496
Specific impairment allowance	22	21
Ending balance	600	517
Analysis of ending balance of finance receivables
Collectively evaluated for impairment	121,048	106,543
Specifically evaluated for impairment	488	549
Financing Receivables	121,536	107,092	$ 116,600
Allowance for credit losses, net investment in operating leases
Beginning balance	71	64
Charge-offs	(51)	(52)
Recoveries	26	24
Other	0	0
Ending balance	71	67
Analysis of ending balance of allowance for credit losses, net investment in operating leases
Collective impairment allowance	71	67
Specific impairment allowance	0	0
Ending balance	71	67
Analysis of ending balance of net investment in operating leases
Collectively evaluated for impairment	26,786	26,495
Individually evaluated for impairment	0	0
Net investment in operating leases before allowance for credit losses	26,786	26,495	26,732
Total allowance
Beginning balance	668	548
Charge-offs	(184)	(177)
Recoveries	66	58
Provision for credit losses	119	152
Other	2	3
Ending balance	671	584
Analysis of Ending Balance of Finance Receivables and Net Investment in Operating Leases [Abstract]
Collective impairment allowance	649	563
Specific impairment allowance	22	21
Ending balance	671	584
Ending balance, net of allowance for credit losses	120,936	106,575	116,003
Ending balance, net investment in operating leases	26,715	26,428	26,661
Net Investment in Operating Leases [Member]
Allowance for credit losses, finance receivables
Provision for credit losses	25	31
Consumer Segment [Member]
Allowance for credit losses, finance receivables
Beginning balance	582	469
Charge-offs	(131)	(123)
Recoveries	39	34
Provision for credit losses	92	121
Other	2	3
Ending balance	584	504
Analysis of ending balance of allowance for credit losses, finance receivables
Collective impairment allowance	563	483
Specific impairment allowance	21	21
Ending balance	584	504
Analysis of ending balance of finance receivables
Collectively evaluated for impairment	75,989	66,075
Specifically evaluated for impairment	380	385
Financing Receivables	76,369	66,460	75,187
Analysis of Ending Balance of Finance Receivables and Net Investment in Operating Leases [Abstract]
Ending balance, net of allowance for credit losses	75,785	65,956
Non-Consumer Segment [Member]
Allowance for credit losses, finance receivables
Beginning balance	15	15
Charge-offs	(2)	(2)
Recoveries	1	0
Provision for credit losses	2	0
Other	0	0
Ending balance	16	13
Analysis of ending balance of allowance for credit losses, finance receivables
Collective impairment allowance	15	13
Specific impairment allowance	1	0
Ending balance	16	13
Analysis of ending balance of finance receivables
Collectively evaluated for impairment	45,059	40,468
Specifically evaluated for impairment	108	164
Financing Receivables	45,167	40,632	$ 41,413
Analysis of Ending Balance of Finance Receivables and Net Investment in Operating Leases [Abstract]
Ending balance, net of allowance for credit losses	$ 45,151	$ 40,619