Segment, Major Customer and Major Supplier Information - Reconciliation from Segment Income to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting [Abstract]
Net income attributable to our common shareholder	$ 151	$ 156
Less: Net (loss) income attributable to noncontrolling interests	(1)	0
Income tax provision	60	54
Income before income tax provision	210	210
Depreciation and amortization	140	131
Interest expense and amortization of debt issuance costs	72	77
Adjustment to reconcile proportional consolidation	13	14
Unrealized gains on change in fair value of derivative instruments, net	(7)	(4)
Realized gains on derivative instruments not included in Adjusted EBITDA	2	(3)
Restructuring and impairment expenses, net	19	3
Loss on sale or disposal of assets, net	1	0
Metal price lag	7	(5)
Other, net	43	(2)
Adjusted EBITDA	500	421
Sierre flood
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Loss from catastrophes	$ 40	$ 0