Segment, Major Customer and Major Supplier Information - Net Sales by Value Stream (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2026	Jun. 30, 2025
Segment Reporting [Line Items]
Net sales	$ 5,793	$ 4,717
Beverage packaging
Segment Reporting [Line Items]
Net sales	3,281	2,494
Automotive
Segment Reporting [Line Items]
Net sales	1,045	1,034
Aerospace and industrial plate
Segment Reporting [Line Items]
Net sales	197	176
Specialty
Segment Reporting [Line Items]
Net sales	$ 1,270	$ 1,013

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details