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Summary of Significant Accounting Policies Credit Risk (Details)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Concentration Risk [Line Items]      
Concentration Risk, Percentage 33.00%us-gaap_ConcentrationRiskPercentage1 38.00%us-gaap_ConcentrationRiskPercentage1 27.00%us-gaap_ConcentrationRiskPercentage1
Valero Marketing And Supply Company [Member]      
Concentration Risk [Line Items]      
Concentration Risk, Percentage 10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByTypeAxis
= qep_ValeroMarketingAndSupplyCompanyMember		    
Freepoint Commodities [Member]      
Concentration Risk [Line Items]      
Concentration Risk, Percentage   13.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByTypeAxis
= qep_FreepointCommoditiesMember		  
Arrow Midstream Holdings LLC [Member]      
Concentration Risk [Line Items]      
Concentration Risk, Percentage   11.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByTypeAxis
= qep_ArrowMidstreamHoldingsLLCMember