Quarterly Financial Data (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010
After tax gain on sale and impairment of assets	$ 1.9	$ 0.4	$ 0.9	$ 0.8	$ 1.5	$ 1.7	$ 0.9	$ 0.3
Tax benefit for the extension of the short line tax credit		3.3	2.5	2.2	7.8
After tax impact of derailment costs	1.3
After-tax gain on legal settlements			0.7		5.1
Segment, Discontinued Operations [Member]
Insurance recoveries, net of tax						2.8
HCRY [Member]
Reversal of accrued restructuring charges after tax						1.5
FreightLink [Member]
Acquisition related income tax benefits	1.9
After-tax acquisition-related costs					16.5	1.9	0.8
After tax acquisiton related foreign currency expense					1.1
AZER [Member]
After-tax acquisition-related costs		$ 1.4