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, 2017	$ 9,524	$ 915	$ 2	$ 25	$ 8,582
Net income	282	0	0	0	282
Other comprehensive loss, net of tax	0	0	0	0	0
Balance at Sep. 30, 2017	9,806	915	2	25	8,864
Balance at Mar. 31, 2018	12,880	915	2	(29)	11,992
Cumulative-effect of change in accounting policy	(110)	0	0	12	(122)
Net income	286	0	0	0	286
Other comprehensive loss, net of tax	(2)	0	0	(2)	0
Balance at Sep. 30, 2018	$ 13,054	$ 915	$ 2	$ (19)	$ 12,156