Inventories (Details) (Work-in-process inventories, USD $)
In Millions, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Work-in-process inventories
   
Inventory [Line Items]    
Costs and estimated earnings in excess of billings on uncompleted contracts $ 122.9 $ 127.9
Excess over average costs on long-term contracts $ 343.4 $ 320.6