Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Other Liabilities, Current [Abstract]
Accruals on completed contracts	$ 306.6	$ 271.9
Deferred income on contracts	414.9	407.6
Contingencies related to contracts	439.7	370.1
Other taxes payable	261.7	143.5
Social security liability	110.6	66.3
Redeemable financial liability	77.0	33.7
Other	825.8	532.2
Total other current liabilities	$ 2,436.3	$ 1,825.3