v3.25.1
Deferred tax - Narrative (Details) - EUR (€)
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of tax attributes and deductible temporary differences € 1,984,900,000 € 1,722,200,000 € 1,882,500,000
Amount of unused tax losses carried forward 862,000,000 798,700,000  
Deferred tax assets 1,474,000 1,126,000  
Expiry between 2028 and 2034      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of unused tax losses carried forward 1,100,000    
Subsidiary companies operating on a cost plus basis      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 1,500,000 1,100,000  
Galapagos Nv (Belgium)      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of unused tax losses carried forward 822,400,000 757,900,000  
Investment Deduction      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of tax attributes and deductible temporary differences 1,000,000 1,000,000 1,000,000
Innovation Income, dividend received deduction and investment deduction      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of tax attributes and deductible temporary differences 566,400,000 410,000,000 365,900,000
Due to innovation income deduction      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of tax attributes and deductible temporary differences 534,400,000 390,300,000 346,200,000
Unrecognized Deferred Tax Assets Excluding Innovation Income Reduction   326,800,000  
All losses including innovation income deduction [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Unrecognized Deferred Tax Assets 490,100,000 424,400,000  
Dividend received deduction carried forward to be offset against future income Screen reader support enabled.      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of tax attributes and deductible temporary differences 31,000,000 18,700,000 18,700,000
Consolidated Tax Losses Carried Forward And Deductible Temporary DIfferences [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Amount of tax attributes and deductible temporary differences € 1,418,500,000 € 1,312,200,000 € 1,516,600,000