v3.25.4
Income Taxes - Components of Income Tax Expense (Benefit) (Detail: Text Values)
€ in Millions
 12 Months Ended
Dec. 31, 2025
EUR (€)
jurisdiction
country
Dec. 31, 2024
EUR (€)
country
Dec. 31, 2023
EUR (€)
Income Taxes [Abstract]      
Reduction/(increase) of total deferred tax expense due to previously unrecognized tax losses and reversal of previous write-downs and expenses from write-downs of deferred tax assets   € 16 € 1,100
Number of jurisdictions in calculation of Pillar Two liability for group entities | jurisdiction 60    
Pillar 2 related current tax expense € 3 € 3  
Blended statutory tax rate across all applicable jurisdictions bottom range 27.00% 28.00%  
CAMT imposed a tax rate on profits before tax 15.00%    
Number of countries apply a statutory tax rate of less 15 percent | country 5 6  
Domestic income tax rate used for calculating deferred tax assets and liabilities 31.30% 31.30% 31.30%
German corporate tax rate, current 15.00%    
German corporate tax rate, after German tax reforms 10.00%    
Positive impact from change in tax law € 97    
Tax benefit from change in tax law 234    
Tax expense from change in tax law recognized in other comprehensive income € 137