Guarantor Consolidating Financial Statements Guarantor Income Statements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Income Statements, Captions [Line Items]
Financial charge income	$ 882	$ 647	$ 1,712	$ 1,062
Leased vehicle income	238	136	438	243
Other income	71	53	138	71
Equity In Income Of Affiliates	0	0	0	0
Revenues	1,191	836	2,288	1,376
Salaries and benefits	154	116	290	190
Other operating expenses	126	75	259	109
Total operating expenses	280	191	549	299
Leased vehicle expenses	179	101	335	181
Provision for loan losses	113	100	248	194
Interest expense	354	164	669	246
Acquisition and integration expenses	0	16	0	22
Costs and Expenses	926	572	1,801	942
Income before income taxes	265	264	487	434
Income Tax provision	(90)	(86)	(167)	(150)
Net income	175	178	320	284
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	224	119	374	219
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Other income	20	35	40	49
Equity In Income Of Affiliates	189	187	359	300
Revenues	209	222	399	349
Salaries and benefits	0	0	0	0
Other operating expenses	(6)	(5)	(5)	(2)
Total operating expenses	(6)	(5)	(5)	(2)
Leased vehicle expenses	0	0	0	0
Provision for loan losses	0	0	0	0
Interest expense	44	50	99	71
Costs and Expenses	38	45	94	69
Income before income taxes	171	177	305	280
Income Tax provision	4	1	15	4
Net income	175	178	320	284
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	224	119	374	219
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Financial charge income	39	30	69	69
Other income	104	83	231	124
Equity In Income Of Affiliates	153	158	269	304
Revenues	296	271	569	497
Salaries and benefits	63	54	116	102
Other operating expenses	41	(24)	74	(49)
Total operating expenses	104	30	190	53
Leased vehicle expenses	0	0	0	0
Provision for loan losses	75	60	135	127
Interest expense	8	54	19	89
Costs and Expenses	187	144	344	269
Income before income taxes	109	127	225	228
Income Tax provision	16	13	16	27
Net income	125	140	241	255
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	148	146	244	262
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Financial charge income	843	617	1,643	993
Leased vehicle income	238	136	438	243
Other income	42	81	80	128
Equity In Income Of Affiliates	0	0	0	0
Revenues	1,123	834	2,161	1,364
Salaries and benefits	91	62	174	88
Other operating expenses	153	104	314	160
Total operating expenses	244	166	488	248
Leased vehicle expenses	179	101	335	181
Provision for loan losses	38	40	113	67
Interest expense	335	206	640	316
Acquisition and integration expenses		16		22
Costs and Expenses	796	529	1,576	834
Income before income taxes	327	305	585	530
Income Tax provision	(110)	(100)	(198)	(181)
Net income	217	205	387	349
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	267	150	442	288
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Other income	(95)	(146)	(213)	(230)
Equity In Income Of Affiliates	(342)	(345)	(628)	(604)
Revenues	(437)	(491)	(841)	(834)
Salaries and benefits	0	0	0	0
Other operating expenses	(62)	0	(124)	0
Total operating expenses	(62)	0	(124)	0
Leased vehicle expenses	0	0	0	0
Provision for loan losses	0	0	0	0
Interest expense	(33)	(146)	(89)	(230)
Costs and Expenses	(95)	(146)	(213)	(230)
Income before income taxes	(342)	(345)	(628)	(604)
Income Tax provision	0	0	0	0
Net income	(342)	(345)	(628)	(604)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ (415)	$ (296)	$ (686)	$ (550)