v3.10.0.1
Property and Equipment - Summary of Property and Equipment (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance € 73  
Ending Balance 197 € 73
Cost    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance 178 162
Additions 145 39
Disposals (47) (13)
Exchange differences 1 (10)
Ending Balance 277 178
Accumulated Depreciation    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance (105) (77)
Depreciation charge (21) (46)
Disposals 45 13
Exchange differences 1 5
Ending Balance (80) (105)
Property and Equipment    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance 21  
Ending Balance 11 21
Property and Equipment | Cost    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance 105 111
Additions 3 10
Disposals (46) (11)
Exchange differences (1) (5)
Ending Balance 61 105
Property and Equipment | Accumulated Depreciation    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance (84) (62)
Depreciation charge (12) (37)
Disposals 45 11
Exchange differences 1 4
Ending Balance (50) (84)
Leasehold Improvements    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance 52  
Ending Balance 186 52
Leasehold Improvements | Cost    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance 73 51
Additions 142 29
Disposals (1) (2)
Exchange differences 2 (5)
Ending Balance 216 73
Leasehold Improvements | Accumulated Depreciation    
Disclosure Of Property Plant And Equipment [Line Items]    
Beginning Balance (21) (15)
Depreciation charge (9) (9)
Disposals   2
Exchange differences   1
Ending Balance € (30) € (21)