Revenue - Contract Balances (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract assets	$ 1,402.9		$ 1,520.0
Contract (liabilities)	4,653.5		4,585.1
Net contract liabilities	(3,250.6)		$ (3,065.1)
Contract assets, increase (decrease)	$ (117.1)
Contract with Customer, Asset, Net, Current, Increase (Decrease), Percent	(7.70%)
Contract (liabilities), (increase) decrease	$ (68.4)
Contract with Customer Liability, Current, Increase (Decrease), Percent	1.50%
Net contract assets (liabilities), increase (decrease)	$ (185.5)
Contract Assets (Liabilities), Current, Net, Increase (Decrease), Percent	(6.10%)
Contract with Customer, Liability, Revenue Recognized	$ 417.1	$ 867.2
Contract with Customer, Performance Obligation Satisfied in Previous Period	$ 57.3	$ 167.7