Deferred Revenue (Details2) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Deferred revenue  
Balance at the beginning of the period $ 426.1
Cash collections 115.1
Revenue recognized from deferred revenue (134.9)
Balance at the end of the period 406.3
U.S. Government | Enhanced View SLA  
Deferred revenue  
Balance at the beginning of the period 210.0
Cash collections 75.0
Revenue recognized from deferred revenue (84.3)
Balance at the end of the period 200.7
U.S. Government | Value Added Services  
Deferred revenue  
Balance at the beginning of the period 77.7
Cash collections 11.3
Revenue recognized from deferred revenue (15.5)
Balance at the end of the period 73.5
U.S. Government | Pre-FOC Payments Related To NextView  
Deferred revenue  
Balance at the beginning of the period 88.8
Revenue recognized from deferred revenue (3.8)
Balance at the end of the period 85.0
Diversified commercial | DAP  
Deferred revenue  
Balance at the beginning of the period 39.4
Cash collections 14.4
Revenue recognized from deferred revenue (15.4)
Balance at the end of the period 38.4
Diversified commercial | Other  
Deferred revenue  
Balance at the beginning of the period 10.2
Cash collections 14.4
Revenue recognized from deferred revenue (15.9)
Balance at the end of the period $ 8.7