CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Millions	Total	Common stock	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2019		100
Beginning Balance at Dec. 31, 2019	$ 6,996	$ 0	$ 4,940	$ 2,083	$ (27)
Increase (Decrease) in Stockholder's Equity
Net income	129			129
Total other comprehensive income	0
Dividends declared to parent	(103)			(103)
Contribution of capital by parent	51		51
Adoption of ASC Topic 326	(1)			(1)
Balance (in shares) at Mar. 31, 2020		100
Ending Balance at Mar. 31, 2020	$ 7,072	$ 0	4,991	2,108	(27)
Balance (in shares) at Dec. 31, 2020	100	100
Beginning Balance at Dec. 31, 2020	$ 7,592	$ 0	5,770	1,846	(24)
Increase (Decrease) in Stockholder's Equity
Net income	167			167
Total other comprehensive income	1				1
Dividends declared to parent	(115)			(115)
Contribution of capital by parent	$ 300		300
Balance (in shares) at Mar. 31, 2021	100	100
Ending Balance at Mar. 31, 2021	$ 7,945	$ 0	$ 6,070	$ 1,898	$ (23)