v3.25.4
Long-Term Debt - Long-Term Debt (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Long-term debt    
Finance leases: $ 103  
Total 2,133 $ 2,953
Less current portion (298) (990)
Total long-term debt, less current portion 1,835 1,963
2.69% due 2028, floating interest rate at Euribor +0.589%    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 90 106
Long-term debt    
Interest rate 2.69%  
Basis spread on floating rate 0.589%  
2.61% due 2029, floating interest rate at Euribor +0.564%    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 115 127
Long-term debt    
Interest rate 2.61%  
Basis spread on floating rate 0.564%  
2.56% due 2031, floating interest rate at Euribor +0.473%    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 236 244
Long-term debt    
Interest rate 2.56%  
Basis spread on floating rate 0.473%  
2.58% due 2031, floating interest rate at Euribor +0.550%    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 116 120
Long-term debt    
Interest rate 2.58%  
Basis spread on floating rate 0.55%  
2.73% due 2033, floating interest rate at Euribor +0.558%    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 282 281
Long-term debt    
Interest rate 2.73%  
Basis spread on floating rate 0.558%  
5.07% due 2034, floating interest rate at Secured Overnight Financing Rate +0.939%    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 270 300
Long-term debt    
Interest rate 5.07%  
Basis spread on floating rate 0.939%  
2.84% due 2027, floating interest rate at Euribor +0.690%    
Long-term debt    
Interest rate 2.84%  
Basis spread on floating rate 0.69%  
2.84% due 2027, floating interest rate at Euribor +0.690% | Credit Facility from Cassa Depositi e Prestiti SpA ("CDP SpA")    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 44 65
2.65% due 2028, floating interest rate at Euribor +0.550%    
Long-term debt    
Interest rate 2.65%  
Basis spread on floating rate 0.55%  
2.65% due 2028, floating interest rate at Euribor +0.550% | Credit Facility from Cassa Depositi e Prestiti SpA ("CDP SpA")    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 59 69
2.95% due 2029, floating interest rate at Euribor +0.850%    
Long-term debt    
Interest rate 2.95%  
Basis spread on floating rate 0.85%  
2.95% due 2029, floating interest rate at Euribor +0.850% | Credit Facility from Cassa Depositi e Prestiti SpA ("CDP SpA")    
Loans Payable [Abstract]    
Bank loans (including current portion) $ 67 74
zero-coupon, due 2025 ("Tranche A") | Dual tranche senior unsecured convertible bonds    
Long-term debt    
Dual tranche senior unsecured convertible bonds $ 0 749
Interest rate 0.00%  
zero-coupon, due 2027 ("Tranche B") | Dual tranche senior unsecured convertible bonds    
Long-term debt    
Dual tranche senior unsecured convertible bonds $ 749 749
Interest rate 0.00%  
3.58% due 2025, fixed interest rate    
Long-term debt    
Finance leases: $ 0 8
Interest rate 3.58%  
0.00% due 2026, fixed interest rate    
Long-term debt    
Finance leases: $ 37 0
Interest rate 0.00%  
3.86% due 2027, fixed interest rate    
Long-term debt    
Finance leases: $ 36 34
Interest rate 3.86%  
3.78% due 2042, fixed interest rate    
Long-term debt    
Finance leases: $ 25 23
Interest rate 3.78%  
1.75% due 2042, fixed interest rate    
Long-term debt    
Finance leases: $ 1 1
Interest rate 1.75%  
4.73% due 2045, fixed interest rate    
Long-term debt    
Finance leases: $ 3 0
Interest rate 4.73%  
5.85% due 2027, fixed interest rate    
Long-term debt    
Finance leases: $ 1 0
Interest rate 5.85%  
0.25% (weighted average), due 2026-2028, fixed interest rate    
Long-term debt    
Other funding program loans $ 2 $ 3
Interest rate 0.25%