Business Segments - Balance Sheet Items (Details) - USD ($) $ in Millions		Mar. 31, 2017	Dec. 31, 2016
Accounts receivable, net:
Accounts receivable, net	[1]	$ 2,209.1	$ 2,344.0
Total assets:
Total assets	[1]	5,263.6	5,412.6
Aviation segment
Accounts receivable, net:
Accounts receivable, net		695.3	776.0
Allowance for bad debt		6.9	6.6
Land segment
Accounts receivable, net:
Accounts receivable, net		758.7	737.5
Allowance for bad debt		8.4	8.2
Marine segment
Accounts receivable, net:
Accounts receivable, net		755.1	830.5
Allowance for bad debt		12.1	10.2
Operating Segments | Aviation segment
Total assets:
Total assets		1,907.0	2,050.6
Operating Segments | Land segment
Total assets:
Total assets		1,914.1	1,928.5
Operating Segments | Marine segment
Total assets:
Total assets		1,249.8	1,287.7
Corporate
Total assets:
Total assets		$ 192.7	$ 145.8

[1] Amounts may not add due to rounding