Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue
Finance charge income									$ 3,256	$ 2,846	$ 2,848
Leased vehicle income									8,606	5,896	2,795
Other income									289	241	224
Total revenue	$ 3,252	$ 3,161	$ 2,990	$ 2,748	$ 2,554	$ 2,360	$ 2,138	$ 1,931	12,151	8,983	5,867
Costs and expenses
Salaries and benefits									845	735	609
Other operating expenses									545	515	442
Total operating expenses									1,390	1,250	1,051
Leased vehicle expenses									6,415	4,506	2,190
Provision for loan losses (Note 4)									757	644	603
Interest expense									2,566	1,972	1,460
Total costs and expenses									11,128	8,372	5,304
Equity income (Note 7)									173	151	116
Income from continuing operations before income taxes	450	186	270	179	242	134	143	138	1,196	762	679
Income tax provision (Note 15)	(240)								111	105	194
Income from continuing operations									1,085	657	485
(Loss) income from discontinued operations, net of tax (Note 2)	(255)	16	(208)	23	12	13	46	26	(424)	97	161
Net income	$ 195	$ 202	$ 62	$ 202	$ 254	$ 147	$ 189	$ 164	661	754	646
Net income attributable to common shareholder									$ 645	$ 754	$ 646