v2.4.0.6
Income Taxes (Details 2) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2008
Deferred tax liabilities relating to:        
Differences between book and tax basis of property $ (913.7) $ (721.7)    
Difference between book and tax basis of intangible (692.1) (702.0)    
Basis difference due to redemption of partnership interests (128.2)      
Total liabilities (1,734.0) (1,423.7)    
Deferred tax assets relating to:        
Environmental reserves 331.3 346.3    
Accruals not currently deductible 310.3 312.8    
Net operating loss carryforwards, state taxes 126.3 127.5    
Difference between book and tax basis of other assets 93.3 68.1    
Deferred taxes on uncertain tax positions 28.9 76.1    
Other 2.0 2.3    
Total assets 892.1 933.1    
Valuation allowance (118.1) (120.1) (126.5) (156.4)
Net deferred tax asset 774.0 813.0    
Net deferred tax liabilities $ (960.0) $ (610.7)