Consolidated Statements of Shareholder's Equity - USD ($) $ in Millions	Total	Capital stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Retained earnings
Balance at Mar. 31, 2021	$ 15,595	$ 915	$ 2	$ 8	$ 14,670
Net income	2,291	0	0	0	2,291
Other comprehensive (loss) income	3	0	0	3	0
Balance at Dec. 31, 2021	17,889	915	2	11	16,961
Balance at Sep. 30, 2021	17,145	915	2	15	16,213
Net income	748	0	0	0	748
Other comprehensive (loss) income	(4)	0	0	(4)	0
Balance at Dec. 31, 2021	17,889	915	2	11	16,961
Balance at Mar. 31, 2022	18,101	915	2	(21)	17,205
Net income	653	0	0	0	653
Other comprehensive (loss) income	(46)	0	0	(46)	0
Balance at Dec. 31, 2022	18,708	915	2	(67)	17,858
Balance at Sep. 30, 2022	18,341	915	2	(70)	17,494
Net income	364	0	0	0	364
Other comprehensive (loss) income	3	0	0	3	0
Balance at Dec. 31, 2022	$ 18,708	$ 915	$ 2	$ (67)	$ 17,858