CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Millions	Total	Common stock	Additional Paid In Capital	Retained Earnings
Balance (in shares) at Dec. 31, 2022		933,000
Beginning Balance at Dec. 31, 2022	$ 1,259	$ 93	$ 761	$ 405
Increase (Decrease) in Stockholder's Equity
Net income	71
Common dividends declared to parent	(49)			(49)
Contribution of capital by parent	45		45
Balance (in shares) at Jun. 30, 2023		933,000
Ending Balance at Jun. 30, 2023	1,326	$ 93	806	427
Balance (in shares) at Mar. 31, 2023		933,000
Beginning Balance at Mar. 31, 2023	1,310	$ 93	791	426
Increase (Decrease) in Stockholder's Equity
Net income	26			26
Common dividends declared to parent	(25)			(25)
Contribution of capital by parent	15		15
Balance (in shares) at Jun. 30, 2023		933,000
Ending Balance at Jun. 30, 2023	$ 1,326	$ 93	806	427
Balance (in shares) at Dec. 31, 2023	933,000	933,000
Beginning Balance at Dec. 31, 2023	$ 1,366	$ 93	843	430
Increase (Decrease) in Stockholder's Equity
Net income	66
Common dividends declared to parent	(36)			(36)
Contribution of capital by parent	$ 183		183
Balance (in shares) at Jun. 30, 2024	933,000	933,000
Ending Balance at Jun. 30, 2024	$ 1,579	$ 93	1,026	460
Balance (in shares) at Mar. 31, 2024		933,000
Beginning Balance at Mar. 31, 2024	1,486	$ 93	938	455
Increase (Decrease) in Stockholder's Equity
Net income	23			23
Common dividends declared to parent	(18)			(18)
Contribution of capital by parent	$ 88		88
Balance (in shares) at Jun. 30, 2024	933,000	933,000
Ending Balance at Jun. 30, 2024	$ 1,579	$ 93	$ 1,026	$ 460