Financial Instruments and Commodity Contracts - Gain (Loss) Reclassification (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Income tax provision (benefit)	$ (64)	$ (50)
Net income from continuing operations	164	96
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Income before income tax provision	(331)	96
Income tax provision (benefit)	89	(26)
Net income from continuing operations	(242)	70
Cash flow hedges \| Metal Contracts \| Income Statement Location [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
Derivative Instruments, Gain (Loss) [Line Items]
Income before income tax provision	(336)	99
Cash flow hedges \| Currency Exchange Contracts \| Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization
Derivative Instruments, Gain (Loss) [Line Items]
Income before income tax provision	4	(2)
Cash flow hedges \| Currency Exchange Contracts \| Income Statement Location [Axis]: us-gaap:DepreciationDepletionAndAmortization
Derivative Instruments, Gain (Loss) [Line Items]
Income before income tax provision	(1)	$ (1)
Cash flow hedges \| Currency Exchange Contracts \| Income Statement Location [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
Derivative Instruments, Gain (Loss) [Line Items]
Income before income tax provision	3
Cash flow hedges \| Interest Rate Swap \| Income Statement Location [Axis]: us-gaap:InterestExpense
Derivative Instruments, Gain (Loss) [Line Items]
Income before income tax provision	$ (1)