CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 851	$ 935	$ 606
Other comprehensive income, net of tax:
Change in unrealized loss on derivatives designated as cash flow hedges	0	(9)	(2)
Change in postretirement plan costs	6	(30)	(18)
Total other comprehensive income (loss), net of tax	6	(39)	(20)
Comprehensive income	$ 857	$ 896	$ 586

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

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