v3.26.1
Fair Value Measurements (Derivative Assets and Liabilities) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Mar. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Netting Adjustment $ (188) $ (59)
Derivative Asset 57 122
Liabilities, Netting Adjustment 188 59
Derivative Liability (642) (54)
Level 2 Instruments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 245 181
Financial Liabilities Fair Value Disclosure (830) (113)
Level 2 Instruments [Member] | Metal contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 197 152
Financial Liabilities Fair Value Disclosure (767) (62)
Level 2 Instruments [Member] | Currency exchange contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 31 23
Financial Liabilities Fair Value Disclosure (57) (45)
Level 2 Instruments [Member] | Energy contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 17 6
Financial Liabilities Fair Value Disclosure (3) (1)
Level 2 Instruments [Member] | Interest rate swap contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 0 0
Financial Liabilities Fair Value Disclosure $ (3) $ (5)