Income Taxes - Tables 3 & 4 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of Deferred Tax Assets [Abstract]
Net Operating Loss Carryforwards	$ 416.5	$ 432.5
Property, net	44.3	40.3
Insurance Reserve	28.5	30.7
Stock-based compensation	26.8	26.8
Allowance for doubtful accounts	15.3	14.9
Alternative minimum tax	11.1	11.9
Carrying value of partnerships	19.8	14.7
Other accruals	19.0	18.9
Capital losses	1.2	6.5
Other	2.0	0.4
Total deferred income tax assets	584.5	597.6
Less: Valuation allowance	(30.7)	(39.8)
Net deferred income tax assets	553.8	557.8
Components of Deferred Tax Liabilities [Abstract]
Intangibles	(29.2)	(26.5)
Convertible debt interest	(28.0)	0
Other	(3.3)	(0.3)
Total deferred income tax liabilities	(60.5)	(26.8)
Net deferred income tax assets	493.3	531.0
Less: Current deferred tax assets	139.0	137.5
Noncurrent deferred tax assets	354.3	393.5
Gross Unrecognized Income Tax Benefits
Gross unrecognized income tax benefits, Beginning Balance	78.0	6.0	12.6
Gross amount of increases in unrecognized tax benefits related to prior periods	46.7	75.8	19.8
Gross amount of decreases in unrecognized tax benefits related to prior periods	(1.9)	(2.5)	(3.0)
Decreases in unrecognized tax benefits relating to settlements with taxing authorities	(121.7)	(0.9)	(20.2)
Reductions to unrecognized tax benefits as a result of a lapse of the applicable statute of limitations		(0.4)	(3.2)
Gross unrecognized income tax benefits, Ending Balance	1.1	78.0	6.0
Unrecognized Tax Benefits, Accrued Interest and Penalties
Unrecognized Tax Benefits, Accrued interest and penalties, Beginning Balance	0	0.1	1.1
Gross amount of increases in unrecognized tax benefits related to prior periods	0.3	0	0
Gross amount of decreases in unrecognized tax benefits related to prior periods	0	0	0
Decreases in unrecognized tax benefits relating to settlements with taxing authorities	0	0	0
Reductions to unrecognized tax benefits as a result of a lapse of the applicable statute of limitations		(0.1)	(1.0)
Unrecognized Tax Benefits, Accrued interest and penalties, Ending Balance	$ 0.3	$ 0	$ 0.1