Consolidated Statements of Shareholder's Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	[1]	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	[1]
Beginning Balance at Dec. 31, 2019	$ 2,587	$ 119		$ 0	$ 161	$ (1,087)	$ 3,513	$ 119
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	104						104
Other comprehensive (loss) income	(78)					(78)
Ending Balance at Jun. 30, 2020	2,732			0	161	(1,165)	3,736
Beginning Balance at Mar. 31, 2020	2,591			0	161	(1,224)	3,654
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	82						82
Other comprehensive (loss) income	59					59
Ending Balance at Jun. 30, 2020	2,732			0	161	(1,165)	3,736
Beginning Balance at Dec. 31, 2020	2,895			0	161	(1,099)	3,833
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	276						276
Other comprehensive (loss) income	(7)					(7)
Ending Balance at Jun. 30, 2021	3,164			0	161	(1,106)	4,109
Beginning Balance at Mar. 31, 2021	3,026			0	161	(1,108)	3,973
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	136						136
Other comprehensive (loss) income	2					2
Ending Balance at Jun. 30, 2021	$ 3,164			$ 0	$ 161	$ (1,106)	$ 4,109

[1] Represents $140 million, net of tax of $21 million, related to the impact as of January 1, 2020, of adopting the Current Expected Credit Loss (CECL) Methodology for the recognition of credit losses on certain financial instruments.