Segment, Major Customer and Major Supplier Information - Net Sales by Value Stream (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Net sales	$ 4,186	$ 4,080	$ 13,647	$ 12,562
Beverage packaging
Segment Reporting Information [Line Items]
Net sales	2,313	2,190	7,336	6,505
Automotive
Segment Reporting Information [Line Items]
Net sales	746	864	2,782	2,686
Aerospace and industrial plate
Segment Reporting Information [Line Items]
Net sales	177	153	548	499
Specialty
Segment Reporting Information [Line Items]
Net sales	$ 950	$ 873	$ 2,981	$ 2,872

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details