Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Financing Revenue and Other Income [Abstract]
Interest and fees on finance receivables and loans	$ 1,582	$ 1,742
Interest on loans held-for-sale	5	2
Interest and dividends on investment securities and other earning assets	131	226
Interest on cash and cash equivalents	4	14
Operating leases	370	367
Total financing revenue and other interest income	2,092	2,351
Interest Expense [Abstract]
Interest on deposits	306	592
Interest on short-term borrowings	1	17
Interest on long-term debt	250	348
Total interest expense	557	957
Net depreciation expense on operating lease assets	163	248
Net financing revenue and other interest income	1,372	1,146
Other revenue [Abstract]
Insurance premiums and service revenue earned	280	277
Gain (loss) on mortgage and automotive loans, net	36	(12)
Loss on Extinguishment of Debt	(1)	0
Other gain (loss) on investments, net	123	(79)
Other income, net of losses	127	80
Total other revenue	565	266
Total net revenue	1,937	1,412
Provision for credit losses	(13)	903
Noninterest Expense [Abstract]
Compensation and benefits expense	395	360
Insurance losses and loss adjustment expenses	63	74
Other operating expenses	485	486
Total noninterest expense	943	920
Income (loss) from continuing operations before income tax expense	1,007	(411)
Statement [Abstract]
Income tax (benefit) expense from continuing operations	211	(92)
Net income from continuing operations	796	(319)
Net income	796	(319)
Other comprehensive income, net of tax	(604)	583
Comprehensive Income	$ 192	$ 264
Earnings Per Share, Basic [Abstract]
Net income (loss) from continuing operations, basic earnings per common share	$ 2.12	$ (0.85)
Net income (loss), basic earnings per common share	2.12	(0.85)
Earnings Per Share, Diluted [Abstract]
Net income (loss) from continuing operations, diluted earnings per common share	2.11	(0.85)
Net income, diluted earnings per common share	2.11	(0.85)
Cash dividends declared per common share	$ 0.19	$ 0.19