Acquisitions (Tables)

12 Months Ended

Dec. 31, 2012

Acquisitions [Abstract]

Schedule of Purchase Price Allocation [Table Text Block]

The following table presents a summary of the preliminary purchase accounting entries:

	As of December 31, 2012
Consideration given:	(in millions)
Cash consideration	$	1,388.7
Amounts recognized for preliminary fair value of assets acquired and liabilities assumed:
Proved properties	$	713.8
Unproved properties	679.4
Asset retirement obligations	(0.9		)
Liabilities assumed	(4.4		)
Other assets acquired	0.8
Total fair value	$	1,388.7

Business Acquisition, Pro Forma Information [Abstract]

	Year ended December 31,
	2012				2011
	Actual		Pro forma		Actual		Pro forma
	(in millions, except per share data)
Revenues	$	2,349.8	$	2,485.3	$	3,159.2	$	3,236.7
Net income attributable to QEP	128.3		143.0		267.2		259.8
Earnings per common share attributable to QEP
Basic	$	0.72	$	0.80	$	1.51	$	1.47
Diluted	0.72		0.80		1.50		1.46