v3.26.1
Financial Instruments and Commodity Contracts (Impact on AOCI and Earnings) (Details) - USD ($)
$ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax $ (811) $ (121) $ 99
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) 2 4 1
Cash flow hedges      
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax (795) (122) 99
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) (2) 0 1
Cash flow hedges | Metal contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax (827) (48) 119
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) (4) 0 0
Cash flow hedges | Currency exchange contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax 31 (77) (12)
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) 2 0 1
Cash flow hedges | Energy contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax 0 4 (8)
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) 0 0 0
Cash flow hedges | Interest rate swap contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax 1 (1) 0
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) 0 0 0
Net investment hedges | Currency exchange contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax (16) 1 0
Amount of Gain (Loss) Recognized in Other expenses (income), net (Ineffective and Excluded Portion) $ 4 $ 4 $ 0