CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 200	$ 187	$ 646	$ 742
Other comprehensive (loss) gain, net of tax:
Change in unrealized gain (loss) on derivatives designated as cash flow hedges	0	3	(2)	(7)
Change in postretirement plan costs	(1)	0	0	0
Total other comprehensive (loss) gain, net of tax	(1)	3	(2)	(7)
Comprehensive income	$ 199	$ 190	$ 644	$ 735