Supplemental Cash Flow Data (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Change in Operating Capital [Abstract]
(Increase) decrease in accounts receivable	$ 779.5	$ 1,019.0
(Increase) decrease in work in process and other current assets	(213.5)	(329.7)
Increase (decrease) in accounts payable	(1,117.5)	(1,551.7)
Increase (decrease) in customer advances and other current liabilities	(13.8)	(23.9)
Change in other assets and liabilities, net	14.7	79.2
Change in operating capital	(550.6)	(807.1)
Income taxes paid	64.8	135.5
Interest paid	$ 53.2	$ 41.5