Business Segments - Income Statement Items (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($)
Information concerning revenue, gross profit and income from operations by segment
Number of reportable operating business segments | segment			3
Revenue:
Total revenue	$ 8,543.0	$ 7,399.8	$ 24,823.4	$ 19,223.6
Gross profit:
Gross profit	239.9	236.7	702.3	676.7
Income from operations:
Income from operations	61.3	58.2	162.8	164.8
Aviation segment
Revenue:
Total revenue	3,705.8	2,969.2	10,531.6	7,810.2
Gross profit:
Gross profit	123.9	111.7	334.8	298.9
Land segment
Revenue:
Total revenue	2,770.5	2,509.8	8,117.9	6,375.9
Gross profit:
Gross profit	85.5	87.8	270.5	261.7
Marine segment
Revenue:
Total revenue	2,066.7	1,920.7	6,173.9	5,037.5
Gross profit:
Gross profit	30.5	37.2	97.0	116.0
Operating Segments
Income from operations:
Income from operations	79.1	76.8	218.4	220.5
Operating Segments | Aviation segment
Income from operations:
Income from operations	61.6	52.6	151.7	123.8
Operating Segments | Land segment
Income from operations:
Income from operations	13.1	13.9	46.7	64.0
Operating Segments | Marine segment
Income from operations:
Income from operations	4.3	10.3	19.9	32.8
Corporate
Income from operations:
Income from operations	$ (17.8)	$ (18.6)	$ (55.5)	$ (55.7)