Guarantor Condensed Consolidating Financial Statements - Guarantor Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities - continuing operations	$ 1,669	$ 1,355
Net cash provided by operating activities - discontinued operations	0	61
Net cash provided by operating activities	1,669	1,416
Cash flows from investing activities
Purchases of retail finance receivables, net	(5,073)	(5,475)
Principal collections and recoveries on retail finance receivables	3,576	2,810
Proceeds from transfer of retail finance receivables, net	0	0
Net collections (funding) of commercial finance receivables	32	(577)
Purchases of leased vehicles, net	(4,496)	(4,760)
Proceeds from termination of leased vehicles	2,379	1,079
Other investing activities	(20)	(20)
Net change in due from affiliates	0	0
Net change in investment in affiliates	0	0
Net cash used in investing activities - continuing operations	(3,602)	(6,943)
Net cash provided by (used in) investing activities - discontinued operations	0	(140)
Net cash used in investing activities	(3,602)	(7,083)
Cash flows from financing activities
Net change in debt (original maturities less than three months)	23	(360)
Borrowings and issuances of secured debt	5,602	8,055
Payments on secured debt	(6,166)	(4,440)
Borrowings and issuances of unsecured debt	3,861	2,968
Payments on unsecured debt	(486)	(531)
Debt issuance costs	(40)	(27)
Dividends paid	(30)	0
Net capital contributions	0	0
Net change in due to affiliates	0	0
Net cash provided by financing activities - continuing operations	2,764	5,665
Net cash provided by (used in) financing activities - discontinued operations	0	(10)
Net cash provided by financing activities	2,764	5,655
Net increase (decrease) in cash, cash equivalents and restricted cash	831	(12)
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	8	37
Cash, cash equivalents and restricted cash at beginning of period	6,567	5,302
Cash, cash equivalents and restricted cash at end of period	7,406	5,327
Cash, cash equivalents and restricted cash at end of period	6,567	5,302	$ 7,406	$ 6,567
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			4,178	4,265
Total	6,567	5,302	7,406	6,567
Continuing Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period	7,406	4,737
Cash, cash equivalents and restricted cash at end of period	7,406	4,737	7,406
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			4,178
Restricted cash included in other assets			3,228
Total	7,406	4,737	7,406
Discontinued Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period	0	590
Cash, cash equivalents and restricted cash at end of period	0	590	0
Supplemental Cash Flow Elements [Abstract]
Total	0	590	0
Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities - continuing operations		0
Net cash provided by operating activities - discontinued operations		0
Net cash provided by operating activities	0	0
Cash flows from investing activities
Purchases of retail finance receivables, net	4,290	2,369
Principal collections and recoveries on retail finance receivables	0	0
Proceeds from transfer of retail finance receivables, net	(4,290)	(2,369)
Net collections (funding) of commercial finance receivables	0	0
Purchases of leased vehicles, net	0	0
Proceeds from termination of leased vehicles	0	0
Other investing activities	28	79
Net change in due from affiliates	4,098	2,150
Net change in investment in affiliates	0	(694)
Net cash used in investing activities - continuing operations		1,535
Net cash provided by (used in) investing activities - discontinued operations		0
Net cash used in investing activities	4,126	1,535
Cash flows from financing activities
Net change in debt (original maturities less than three months)	0	0
Borrowings and issuances of secured debt	(28)	(79)
Payments on secured debt	0	0
Borrowings and issuances of unsecured debt	0	0
Payments on unsecured debt	0	0
Debt issuance costs	0	0
Dividends paid	0
Net capital contributions	0	694
Net change in due to affiliates	(4,098)	(2,150)
Net cash provided by financing activities - continuing operations		(1,535)
Net cash provided by (used in) financing activities - discontinued operations		0
Net cash provided by financing activities	(4,126)	(1,535)
Net increase (decrease) in cash, cash equivalents and restricted cash	0	0
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0	0
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			0	0
Total	0	0	0	0
Eliminations [Member] | Continuing Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			0
Restricted cash included in other assets			0
Total	0	0	0
Eliminations [Member] | Discontinued Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period		0
Cash, cash equivalents and restricted cash at end of period		0
Supplemental Cash Flow Elements [Abstract]
Total		0
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities - continuing operations		(273)
Net cash provided by operating activities - discontinued operations		0
Net cash provided by operating activities	(324)	(273)
Cash flows from investing activities
Purchases of retail finance receivables, net	0	0
Principal collections and recoveries on retail finance receivables	0	0
Proceeds from transfer of retail finance receivables, net	0	0
Net collections (funding) of commercial finance receivables	0	0
Purchases of leased vehicles, net	0	0
Proceeds from termination of leased vehicles	0	0
Other investing activities	0	0
Net change in due from affiliates	(2,726)	(2,230)
Net change in investment in affiliates	(5)	0
Net cash used in investing activities - continuing operations		(2,230)
Net cash provided by (used in) investing activities - discontinued operations		0
Net cash used in investing activities	(2,731)	(2,230)
Cash flows from financing activities
Net change in debt (original maturities less than three months)	48	17
Borrowings and issuances of secured debt	0	0
Payments on secured debt	0	0
Borrowings and issuances of unsecured debt	3,053	2,497
Payments on unsecured debt	0	0
Debt issuance costs	(16)	(11)
Dividends paid	(30)
Net capital contributions	0	0
Net change in due to affiliates	0	0
Net cash provided by financing activities - continuing operations		2,503
Net cash provided by (used in) financing activities - discontinued operations		0
Net cash provided by financing activities	3,055	2,503
Net increase (decrease) in cash, cash equivalents and restricted cash	0	0
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0	0
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			0	0
Total	0	0	0	0
Parent Company [Member] | Continuing Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			0
Restricted cash included in other assets			0
Total	0	0	0
Parent Company [Member] | Discontinued Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period		0
Cash, cash equivalents and restricted cash at end of period		0
Supplemental Cash Flow Elements [Abstract]
Total		0
Guarantor [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities - continuing operations		117
Net cash provided by operating activities - discontinued operations		(14)
Net cash provided by operating activities	(47)	103
Cash flows from investing activities
Purchases of retail finance receivables, net	(5,289)	(4,920)
Principal collections and recoveries on retail finance receivables	828	450
Proceeds from transfer of retail finance receivables, net	3,135	2,095
Net collections (funding) of commercial finance receivables	(322)	(194)
Purchases of leased vehicles, net	0	0
Proceeds from termination of leased vehicles	0	0
Other investing activities	(44)	(98)
Net change in due from affiliates	(1,372)	80
Net change in investment in affiliates	0	694
Net cash used in investing activities - continuing operations		(1,893)
Net cash provided by (used in) investing activities - discontinued operations		0
Net cash used in investing activities	(3,064)	(1,893)
Cash flows from financing activities
Net change in debt (original maturities less than three months)	0	0
Borrowings and issuances of secured debt	0	0
Payments on secured debt	0	0
Borrowings and issuances of unsecured debt	0	0
Payments on unsecured debt	0	0
Debt issuance costs	0	0
Dividends paid	0
Net capital contributions	0	0
Net change in due to affiliates	2,662	1,546
Net cash provided by financing activities - continuing operations		1,546
Net cash provided by (used in) financing activities - discontinued operations		0
Net cash provided by financing activities	2,662	1,546
Net increase (decrease) in cash, cash equivalents and restricted cash	(449)	(244)
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	3,535	2,284
Cash, cash equivalents and restricted cash at end of period	3,086	2,040
Cash, cash equivalents and restricted cash at end of period	3,535	2,284	3,086	3,535
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			3,086	3,535
Total	3,535	2,284	3,086	3,535
Guarantor [Member] | Continuing Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period	3,086	2,040
Cash, cash equivalents and restricted cash at end of period	3,086	2,040	3,086
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			3,086
Restricted cash included in other assets			0
Total	3,086	2,040	3,086
Guarantor [Member] | Discontinued Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period		0
Cash, cash equivalents and restricted cash at end of period		0
Supplemental Cash Flow Elements [Abstract]
Total		0
Non-Guarantors [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities - continuing operations		1,511
Net cash provided by operating activities - discontinued operations		75
Net cash provided by operating activities	2,040	1,586
Cash flows from investing activities
Purchases of retail finance receivables, net	(4,074)	(2,924)
Principal collections and recoveries on retail finance receivables	2,748	2,360
Proceeds from transfer of retail finance receivables, net	1,155	274
Net collections (funding) of commercial finance receivables	354	(383)
Purchases of leased vehicles, net	(4,496)	(4,760)
Proceeds from termination of leased vehicles	2,379	1,079
Other investing activities	(4)	(1)
Net change in due from affiliates	0	0
Net change in investment in affiliates	5	0
Net cash used in investing activities - continuing operations		(4,355)
Net cash provided by (used in) investing activities - discontinued operations		(140)
Net cash used in investing activities	(1,933)	(4,495)
Cash flows from financing activities
Net change in debt (original maturities less than three months)	(25)	(377)
Borrowings and issuances of secured debt	5,630	8,134
Payments on secured debt	(6,166)	(4,440)
Borrowings and issuances of unsecured debt	808	471
Payments on unsecured debt	(486)	(531)
Debt issuance costs	(24)	(16)
Dividends paid	0
Net capital contributions	0	(694)
Net change in due to affiliates	1,436	604
Net cash provided by financing activities - continuing operations		3,151
Net cash provided by (used in) financing activities - discontinued operations		(10)
Net cash provided by financing activities	1,173	3,141
Net increase (decrease) in cash, cash equivalents and restricted cash	1,280	232
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	8	37
Cash, cash equivalents and restricted cash at beginning of period	3,032	3,018
Cash, cash equivalents and restricted cash at end of period	4,320	3,287
Cash, cash equivalents and restricted cash at end of period	3,032	3,018	4,320	3,032
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			1,092	730
Total	3,032	3,018	4,320	$ 3,032
Non-Guarantors [Member] | Continuing Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period	4,320	2,697
Cash, cash equivalents and restricted cash at end of period	4,320	2,697	4,320
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents			1,092
Restricted cash included in other assets			3,228
Total	$ 4,320	2,697	$ 4,320
Non-Guarantors [Member] | Discontinued Operations [Member]
Cash flows from financing activities
Cash, cash equivalents and restricted cash at end of period		590
Cash, cash equivalents and restricted cash at end of period		590
Supplemental Cash Flow Elements [Abstract]
Total		$ 590