XML 81 R57.htm IDEA: XBRL DOCUMENT v3.20.4
Revenue recognition - Additional Information (Detail) - EUR (€)
€ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Contract liabilities [abstract]      
Deferred revenue € 380 € 319  
Description of when entity typically satisfies performance obligations over a period up to a year    
Revenue recognition € 301 € 248 € 210