Income Taxes (Deferred tax liabilities and assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Depreciation	$ 295.2	$ 327.8
Deferred revenue	17.2	12.2
Intangibles	29.5	36.3
Gain on debt redemption	64.3	63.9
Other	54.7	54.7
Deferred tax liabilities	460.9	494.9
Claims and insurance	(169.2)	(179.6)
Net operating loss carryforwards	(329.1)	(298.8)
Employee benefit accruals	(237.9)	(288.9)
Other	(176.7)	(173.6)
Deferred tax assets	(912.9)	(940.9)
Valuation allowance	454.1	448.4
Net deferred tax assets	(458.8)	(492.5)
Net deferred tax liability	$ 2.1	$ 2.4