XML 53 R43.htm IDEA: XBRL DOCUMENT v3.7.0.1
Significant Accounting Policies (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Property, Plant and Equipment [Line Items]    
Gain (loss) on disposition of assets $ (5.1) $ 0.2
Recognized impairments 7.0 $ 873.3
Permian Basin    
Property, Plant and Equipment [Line Items]    
Gain (loss) on disposition of assets $ (5.1)