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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Debt - Schedule of Debt (Details) ¥ in Millions, SFr in Millions, $ in Millions	3 Months Ended
	Jun. 30, 2026 USD ($)	Jun. 30, 2026 CNY (¥)	Jun. 30, 2026 CHF (SFr)	Mar. 31, 2026 USD ($)	Mar. 31, 2026 CNY (¥)	Mar. 31, 2026 CHF (SFr)	Dec. 31, 2025	Aug. 18, 2025	Jun. 30, 2025 CNY (¥)
Debt Instrument
Short-term borrowings	$ (2,284)			$ (1,305)
Long-term debt, principal	6,630			6,619
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Less: Current portion of long-term debt	0			0
Unamortized Carrying Value Adjustments	(63)			(68)
Long-term debt, Carrying Value	6,570			6,572
Current portion of long-term debt	(56)			(54)
Long-term debt, net of current portion, Carrying Value	6,567			6,551
Total debt	8,970			7,978
Total debt, Carrying Value	8,907			7,910
Leased assets obtained in exchange for new finance lease liabilities	$ 21
China Bank Loans, due August 2027
Debt Instrument
Stated rate	2.65%	2.65%	2.65%
Long-term debt, principal	$ 29	¥ 200		29
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 29			29
China Loan, due September 2027
Debt Instrument
Stated rate	2.45%	2.45%	2.45%
Long-term debt, principal	$ 15	¥ 100		14	¥ 100
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 15			14
China Loan, due November 2027
Debt Instrument
Stated rate	2.60%	2.60%	2.60%
Long-term debt, principal	$ 22	¥ 149		22					¥ 150
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 22			22
China Loan, due December 2027
Debt Instrument
Stated rate	2.50%	2.50%	2.50%
Long-term debt, principal	$ 22	¥ 149		22					¥ 150
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 22			22
China Loan, due January 2029
Debt Instrument
Stated rate	2.40%	2.40%	2.40%
Long-term debt, principal	$ 27	¥ 180		26	¥ 180
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 27			$ 26
Interest rate, effective percentage				0.60%	0.60%	0.60%
Sierre Loan, due October 2027
Debt Instrument
Stated rate	0.46%	0.46%	0.46%
Long-term debt, principal	$ 124		SFr 100	$ 125		SFr 100
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 124			125
Interest rate, effective percentage							0.50%
Series 2025A Bonds, due June 2032
Debt Instrument
Stated rate	5.00%	5.00%	5.00%
Long-term debt, principal	$ 400			400
Long-term debt, Unamortized Carrying Value Adjustments	(5)			(5)
Long-term debt, Carrying Value	$ 395			395
Series 2025 B Bonds, due June 2032
Debt Instrument
Stated rate	4.625%	4.625%	4.625%
Long-term debt, principal	$ 100			100
Long-term debt, Unamortized Carrying Value Adjustments	(2)			(2)
Long-term debt, Carrying Value	$ 98			98
Series 2026A Bonds, due March 2033
Debt Instrument
Stated rate	4.30%	4.30%	4.30%
Long-term debt, principal	$ 225			225
Long-term debt, Unamortized Carrying Value Adjustments	(4)			(4)
Long-term debt, Carrying Value	$ 221			221
Finance lease obligations and other debt, due through April 2040(5)
Debt Instrument
Stated rate	4.54%	4.54%	4.54%
Long-term debt, principal	$ 53			33
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 53			33
Term Loan \| Floating rate Term Loans, due March 2032
Debt Instrument
Stated rate	5.48%	5.48%	5.48%
Long-term debt, principal	$ 1,234			1,238
Long-term debt, Unamortized Carrying Value Adjustments	(13)			(14)
Long-term debt, Carrying Value	$ 1,221			1,224
Senior Notes \| Senior Notes due November 2026
Debt Instrument
Stated rate	3.25%	3.25%	3.25%
Long-term debt, principal	$ 13			13
Long-term debt, Unamortized Carrying Value Adjustments	0			0
Long-term debt, Carrying Value	$ 13			13
Senior Notes \| Senior Notes due April 2029
Debt Instrument
Stated rate	3.375%	3.375%	3.375%
Long-term debt, principal	$ 572			576
Long-term debt, Unamortized Carrying Value Adjustments	(4)			(5)
Long-term debt, Carrying Value	$ 568			571
Senior Notes \| Senior Notes Due 2030
Debt Instrument
Stated rate	4.75%	4.75%	4.75%
Long-term debt, principal	$ 1,600			1,600
Long-term debt, Unamortized Carrying Value Adjustments	(11)			(12)
Long-term debt, Carrying Value	1,589			1,588
Senior Notes \| 6.875% Senior Notes, due January 2030
Debt Instrument
Long-term debt, principal	750			750
Long-term debt, Unamortized Carrying Value Adjustments	(8)			(9)
Long-term debt, Carrying Value	$ 742			741
Interest rate, effective percentage	6.875%	6.875%	6.875%
Senior Notes \| Senior Notes due August 2031
Debt Instrument
Stated rate	3.875%	3.875%	3.875%
Long-term debt, principal	$ 750			750
Long-term debt, Unamortized Carrying Value Adjustments	(6)			(6)
Long-term debt, Carrying Value	$ 744			744
Senior Notes \| 6.375% Senior Notes due August 2033
Debt Instrument
Stated rate	6.375%	6.375%	6.375%					6.375%
Long-term debt, principal	$ 750			750
Long-term debt, Unamortized Carrying Value Adjustments	(10)			(11)
Long-term debt, Carrying Value	$ 740			$ 739