Supplemental Cash Flow Data (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Change in Operating Capital [Abstract]
(Increase) decrease in accounts receivable	$ 460.3	$ 891.3
(Increase) decrease in work in process and other current assets	(277.5)	(188.5)
Increase (decrease) in accounts payable	(785.9)	(1,413.4)
Increase (decrease) in customer advances and other current liabilities	(412.1)	(357.4)
Change in other assets and liabilities, net	(113.3)	(73.5)
Change in operating capital	(1,128.5)	(1,141.5)
Income taxes paid	339.0	362.5
Interest paid	$ 111.2	$ 106.8