Fair Value Measurements - Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2025	Mar. 31, 2025
Fair Value, Concentration of Risk, Financial Assets, Balance Sheet Groupings [Abstract]
Total debt - third parties (excluding short term borrowings), fair value	$ 6,438	$ 5,652
Total debt - third parties (excluding short term borrowings), carrying value	6,342	5,790
Other Assets, Fair Value Disclosure	5	3
Related Party
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Parties	$ 5	$ 3

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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+ Details

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

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