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Debt (Loans) (Details) ¥ in Millions, SFr in Millions, $ in Millions	1 Months Ended	3 Months Ended					12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2024 CNY (¥)	Dec. 31, 2024 CHF (SFr)	Sep. 30, 2024 CNY (¥)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2025 CNY (¥)	Mar. 31, 2025 CHF (SFr)
Debt Instrument [Line Items]
Long-term debt, carrying value							$ 5,790	$ 4,876
Proceeds from issuance of long-term and short-term borrowings							2,268	749	$ 50
Long-term debt, principal							5,832	4,914
Loss on extinguishment of debt, net							7	5	$ 0
China Loan, Due September 2027
Debt Instrument [Line Items]
Long-term debt, carrying value							13	0
Proceeds from issuance of long-term and short-term borrowings \| ¥				¥ 100
Interest rates				0.55%
Long-term debt, principal							13	0		¥ 100
China Loan, due November 2027
Debt Instrument [Line Items]
Long-term debt, carrying value							21	0
Proceeds from issuance of long-term and short-term borrowings \| ¥		¥ 150
Interest rates		0.40%	0.40%
Long-term debt, principal							21	0		150
China Loan, due December 2027
Debt Instrument [Line Items]
Long-term debt, carrying value							21	0
Proceeds from issuance of long-term and short-term borrowings \| ¥		¥ 150
Interest rates		0.50%	0.50%
Long-term debt, principal							21	0		150
Sierre Loan, due October 2027
Debt Instrument [Line Items]
Long-term debt, carrying value							113	0
Proceeds from issuance of long-term and short-term borrowings \| SFr			SFr 100
Interest rates		0.50%	0.50%
Long-term debt, principal							$ 113	$ 0			SFr 100
China Bank Loans, due August 2027
Debt Instrument [Line Items]
Long-term debt, carrying value \| ¥										300
Brazil Loan, due June 2023
Debt Instrument [Line Items]
Proceeds from issuance of long-term and short-term borrowings	$ 30
Interest rates	1.80%
Extinguishment of debt						$ 30
Brazil Loan, due December 2023
Debt Instrument [Line Items]
Proceeds from issuance of long-term and short-term borrowings	$ 20
Interest rates	1.80%
Extinguishment of debt					$ 20
China \| Maximum
Debt Instrument [Line Items]
Unsecured debt \| ¥										¥ 500