v3.26.3
Financial Instruments - Interest bearing loans and borrowings (Details)
€ in Millions, $ in Millions
 2 Months Ended 3 Months Ended 9 Months Ended 84 Months Ended
Nov. 10, 2025
EUR (€)
Dec. 31, 2025
EUR (€)
Dec. 31, 2026
EUR (€)
Sep. 30, 2026
EUR (€)
Sep. 30, 2026
USD ($)
Jul. 15, 2033
EUR (€)
Nov. 10, 2032
EUR (€)
Sep. 30, 2026
USD ($)
Jul. 30, 2026
EUR (€)
Nov. 10, 2025
USD ($)
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Discount on issuance of debt € 3.5                  
Borrowing costs capitalised           € 6.1 € 1.2      
Loans and borrowings   € 2,258.6   € 2,279.2            
Net loss on refinancing 75.9                  
Disclosure of detailed information about borrowings [line items]                    
Line of credit facility, maximum borrowing capacity € 175.0                  
Financial assets at fair value through profit or loss, category [member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Non-cash loss recognized in relation to cross currency interest rate swaps   5.6                
Loans and Borrowings [Member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Fair value   2,201.1   2,211.9            
Carrying value   2,201.9   2,217.2            
Loans and Borrowings [Member] | Deferred borrowing costs                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Fair value   0.0   0.0            
Carrying value   (6.2)   (10.1)            
Senior EUR/USD loans | Loans and Borrowings [Member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Carrying value   1,408.0   1,427.2            
Senior EUR/USD loans | Loans and Borrowings [Member] | Level 2                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Fair value   1,417.0   1,422.3            
Other borrowings [Domain] | Loans and Borrowings [Member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Fair value   0.1   0.1            
Carrying value   0.1   € 0.1            
Twenty Twenty-Eight Fixed Rate Senior Secured Notes                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Interest rate       5.25%       5.25%    
Twenty Twenty-Eight Fixed Rate Senior Secured Notes | Gross carrying amount [member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Loans and borrowings       € 800.0            
Twenty Twenty-Eight Fixed Rate Senior Secured Notes | Loans and Borrowings [Member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Carrying value   800.0   800.0            
Twenty Twenty-Eight Fixed Rate Senior Secured Notes | Loans and Borrowings [Member] | Level 1                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Fair value   € 784.0   789.5            
Senior USD Debt                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Notional amount       547.2       $ 620.0   $ 679.1
Interest rate 2.50%                 2.50%
Repayments of non-current borrowings       € 5.5 $ 6.2          
Repayments Of Non-current Borrowings - percentage of original issued notional       100.00%       100.00%    
Disclosure of detailed information about borrowings [line items]                    
Notional amount       € 547.2       $ 620.0   $ 679.1
Repayments Of Non-current Borrowings - percentage of original issued notional       100.00%       100.00%    
Senior EURO Debt                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Notional amount € 553.2                  
Interest rate 2.50%                 2.50%
Disclosure of detailed information about borrowings [line items]                    
Notional amount € 553.2                  
Senior Eur Debt                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Notional amount       € 880.0            
Interest rate       2.50%       2.50%    
Disclosure of detailed information about borrowings [line items]                    
Notional amount       € 880.0            
Senior EUR Debt                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Notional amount 130.0     880.0            
Interest rate   2.75%                
Disclosure of detailed information about borrowings [line items]                    
Notional amount € 130.0     € 880.0            
Repayments of current borrowings     € 100.0              
2033 Fixed Rate Senior Secured Notes                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Interest rate                 5.25%  
2033 Fixed Rate Senior Secured Notes | Gross carrying amount [member]                    
Disclosure Of Financial Assets And Liabilities [Table] [Line Items]                    
Loans and borrowings                 € 800.0