Consolidated Statements of Shareholder's Equity - USD ($) $ in Millions		Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2018		$ 2,196	$ 0	$ 161	$ (1,060)	$ 3,095
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		103				103
Other comprehensive income (loss)		7			7	0
Ending Balance at Mar. 31, 2019		2,306	0	161	(1,053)	3,198
Beginning Balance at Dec. 31, 2019		2,587	0	161	(1,087)	3,513
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting guidance, before tax | Accounting Standards Update 2016-13 [Member]		140
Adoption of new accounting guidance, tax | Accounting Standards Update 2016-13 [Member]		21
Beginning Balance at Dec. 31, 2019		2,587	0	161	(1,087)	3,513
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		22				22
Other comprehensive income (loss)		(137)			(137)	0
Ending Balance at Mar. 31, 2020		2,591	$ 0	$ 161	$ (1,224)	3,654
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle - Reserve for Credit Losses | Accounting Standards Update 2016-13 [Member]	[1]	$ 119				$ 119

[1] Represents $140 million, net of tax of $21 million, relating to the impact as of January 1, 2020, of adopting the new accounting guidance for the recognition of credit losses on certain financial instruments.