Rendering

Component: (Network and Table)
Network
2454404 - Disclosure - Employee Benefit Plans (Schedule of Change in Plan Assets) (Details)
(http://www.alxn.com/role/EmployeeBenefitPlansScheduleOfChangeInPlanAssetsDetails)
Table(Implied)
Slicers (applies to each fact value in each table cell)
Reporting Entity [Axis]0000899866 (http://www.sec.gov/CIK)
Compensation and Retirement Disclosure [Abstract]Period [Axis]
2016-01-01 - 2016-12-31
2015-01-01 - 2015-12-31
2014-01-01 - 2014-12-31
Compensation and Retirement Disclosure [Abstract]
 
 
 
Change in plan assets:
 
 
 
Fair value of plan assets, beginning of year
22,000,000  
27,000,000  
 
Return on plan assets
0  
0  
 
Employer contributions
3,000,000  
4,000,000  
 
Plan participants' contributions
2,000,000  
2,000,000  
2,000,000  
Curtailment
0  
(13,000,000) 
 
Foreign currency exchange rate changes
(1,000,000) 
0  
 
Net transfers to (from) plan
0  
2,000,000  
 
Other
2,000,000  
0  
 
Fair value of plan assets, end of year
28,000,000  
 
22,000,000  
 
27,000,000  
 
Funded status at end of year
(20,000,000) 
(23,000,000)