Income Taxes (Domestic and Foreign Components) (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Domestic (Canada)	$ 161	$ 92	$ 73
Foreign (all other countries)	(143)	747	741
Pre-tax income before equity in net loss (income) of non-consolidated affiliates	$ 18	$ 839	$ 814

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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+ Details