Rendering

Component: (Network and Table)
Network
2454403 - Disclosure - Employee Benefit Plans (Schedule of Change in Benefit Obligation) (Details)
(http://www.alxn.com/role/EmployeeBenefitPlansScheduleOfChangeInBenefitObligationDetails)
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]
 
 
 
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
 
 
 
Projected benefit obligation, beginning of year
45,000,000  
51,000,000  
 
Prior service cost
0  
0  
 
Service cost
8,000,000  
10,000,000  
8,000,000  
Interest cost
0  
1,000,000  
1,000,000  
Change in assumptions
(1,000,000) 
2,000,000  
 
Recognized actuarial net loss
0  
4,000,000  
 
Curtailment
0  
(25,000,000) 
 
Plan amendment
(4,000,000) 
0  
 
Foreign currency exchange rate changes
(3,000,000) 
0  
 
Net transfers to (from) plan
0  
2,000,000  
 
Other
3,000,000  
0  
 
Projected benefit obligation, end of year
48,000,000  
 
45,000,000  
 
51,000,000  
 
Accumulated benefit obligation, end of year
41,000,000  
42,000,000