Qep Resources (QEP) 10-Q 5 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013
Document and Entity Information [Abstract]	'
Entity Registrant Name	'QEP RESOURCES, INC.
Entity Central Index Key	'0001108827
Current Fiscal Year End Date	'--12-31
Entity Well-known Seasoned Issuer	'Yes
Entity Voluntary Filers	'No
Entity Current Reporting Status	'Yes
Entity Filer Category	'Large Accelerated Filer
Entity Common Stock, Shares Outstanding	179,281,102
Document Fiscal Year Focus	'2013
Document Fiscal Period Focus	'Q3
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	30-Sep-13

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
REVENUES	'	'	'	'
Natural gas sales	$194.80	$170.30	$610.50	$470.40
Oil sales	253.8	117.7	656.3	335.7
NGL sales	71.3	67.5	215	247
Gathering, processing and other	46.9	46.3	135.1	141.9
Purchased gas, oil and NGL sales	206	140.6	603.4	449.9
Total Revenues	772.8	542.4	2,220.30	1,644.90
OPERATING EXPENSES	'	'	'	'
Purchased gas, oil and NGL expense	205	142.6	608.8	455.9
Lease operating expense	45	42.2	127.4	122.8
Natural gas, oil and NGL transportation and other handling costs	34.5	36.3	105.8	111.5
Gathering, processing and other	22.4	22.1	66.5	66.4
General and administrative	49.3	41.7	136.2	114.5
Production and property taxes	42.5	24.3	117.7	68.4
Depreciation, depletion and amortization	253.1	234.6	757.1	648.3
Exploration expenses	1.8	2.2	9.5	6.3
Impairment	3.8	9	4	70.9
Total Operating Expenses	657.4	555	1,933	1,665
Net (loss) gain from asset sales	12.8	0	113	1.5
OPERATING INCOME	128.2	-12.6	400.3	-18.6
Realized and unrealized (losses) gains on derivative contracts (See Note 8)	-27.8	36.1	51.6	334.7
Interest and other income	4	-0.2	9.1	2.4
Income from unconsolidated affiliates	0.8	2.3	3.7	5.6
Loss from early extinguishment of debt	0	0	0	-0.6
Interest expense	-41.7	-30	-122.5	-82.9
(LOSS) INCOME BEFORE INCOME TAXES	63.5	-4.4	342.2	240.6
Income tax benefit (provision)	-22.4	2.3	-125	-86.5
NET (LOSS) INCOME	41.1	-2.1	217.2	154.1
Net income attributable to noncontrolling interest	-3.8	-1	-5.8	-2.7
NET (LOSS) INCOME ATTRIBUTABLE TO QEP	$37.30	($3.10)	$211.40	$151.40
Earnings Per Common Share Attributable to QEP	'	'	'	'
Basic total (in dollars per share)	$0.21	($0.02)	$1.18	$0.85
Diluted total (in dollars per share)	$0.21	($0.02)	$1.18	$0.85
Weighted-average common shares outstanding	'	'	'	'
Used in basic calculation (in shares)	179.3	177.9	179.2	177.6
Used in diluted calculation (in shares)	179.5	177.9	179.4	178.6
Dividends per common share (in dollars per share)	$0.02	$0.02	$0.06	$0.06

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]	'		'		'		'
Net (loss) income	$41.10		($2.10)		$217.20		$154.10
Other comprehensive (loss) income, net of tax:	'		'		'		'
Reclassification of previously deferred derivative gains(1)	-19.7	[1]	-42.1	[1]	-60.4	[1]	-133.8	[1]
Pension and other postretirement plans adjustments:	'		'		'		'
Amortization of net actuarial loss	0.4	[2]	0.5	[2]	1.1	[2]	0.7	[2]
Amortization of prior service cost	0.8	[3]	0.9	[3]	2.5	[3]	2.6	[3]
Total pension and other postretirement plans adjustments	1.2		1.4		3.6		3.3
Other comprehensive loss	-18.5		-40.7		-56.8		-130.5
Comprehensive (loss) income	22.6		-42.8		160.4		23.6
Comprehensive income attributable to noncontrolling interests	-3.8		-1		-5.8		-2.7
Comprehensive (loss) income attributable to QEP	$18.80		($43.80)		$154.60		$20.90
[1]	Presented net of income tax benefit of $11.7 million and $35.8 million during the three and nine months ended September 30, 2013 and $24.9 million and $79.2 million during the three and nine months ended September 30, 2012, respectively.
[2]	Presented net of income tax expense of $0.2 million and $0.7 million during the three and nine months ended September 30, 2013 and $0.2 million and $0.4 million during the three and nine months ended September 30, 2012, respectively.
[3]	Presented net of income tax expense of $0.5 million and $1.5 million and during the three and nine months ended September 30, 2013 and $0.5 million and $1.6 million during the three and nine months ended September 30, 2012, respectively.

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other comprehensive income (loss), tax	'	'	'	'
Tax expense (benefit) on gains (losses) on changes in unrealized fair value of derivatives designated as cash flow hedges	$11.70	$24.90	$35.80	$79.20
Pension and other postretirement plans adjustments:	'	'	'	'
Tax expense (benefit) on net unamortized gain (loss) incurred	-0.2	-0.2	-0.7	-0.4
Tax expense (benefit) on prior service cost incurred	($0.50)	($0.50)	($1.50)	($1.60)

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current Assets	'	'
Cash and cash equivalents	$123	$0
Accounts receivable, net	321.9	387.5
Fair value of derivative contracts	39.4	188.7
Gas, oil and NGL inventories at lower of average cost or market	13.1	13.1
Prepaid expenses and other	49.4	68
Deferred income taxes	0	0
Total Current Assets	546.8	657.3
Property, Plant and Equipment (successful efforts method for gas and oil properties)	'	'
Proved properties	11,038.80	10,234.30
Unproved properties	911.8	937.9
Midstream field services	1,670.40	1,634.90
Marketing and other	80.4	64.6
Material and supplies	63.4	61.9
Total Property, Plant and Equipment	13,764.80	12,933.60
Less Accumulated Depreciation, Depletion and Amortization	'	'
Exploration and production	4,747.40	4,258.10
Midstream field services	394.7	357.9
Marketing and other	20.3	18.1
Total Accumulated Depreciation, Depletion and Amortization	5,162.40	4,634.10
Net Property, Plant and Equipment	8,602.40	8,299.50
Investment in unconsolidated affiliates	39	41.2
Goodwill	59.5	59.5
Fair value of derivative contracts	5.8	4.1
Other noncurrent assets	53.2	46.9
TOTAL ASSETS	9,306.70	9,108.50
Current Liabilities	'	'
Checks outstanding in excess of cash balances	1.6	39.7
Accounts payable and accrued expenses	593.6	643.4
Production and property taxes	58	41.8
Interest payable	34.6	36.9
Fair value of derivative contracts	10.1	2.6
Deferred income taxes	9.5	5
Total Current Liabilities	707.4	769.4
Long-term debt	2,882.30	3,206.90
Deferred income taxes	1,494.70	1,493.50
Asset retirement obligations	168.4	191.4
Fair value of derivative contracts	0	3.6
Other long-term liabilities	129	130
Commitments and contingencies	'	'
EQUITY	'	'
Common stock - par value $0.01 per share; 500.0 million shares authorized; 179.3 million and 178.5 million shares issued, respectively	1.8	1.8
Treasury stock - 0.4 million and 0.1 million shares, respectively	-14.7	-3.7
Additional paid-in capital	489.3	462.1
Retained earnings	2,973.70	2,773
Accumulated other comprehensive income	-24	32.8
Total Common Shareholders' Equity	3,426.10	3,266
Noncontrolling interest	498.8	47.7
Total Equity	3,924.90	3,313.70
TOTAL LIABILITIES AND EQUITY	$9,306.70	$9,108.50

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, except Per Share data, unless otherwise specified
EQUITY	'	'
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	500	500
Common stock, shares issued (in shares)	179.3	178.5
Treasury stock (in shares)	0.4	0.1

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
OPERATING ACTIVITIES	'	'
Net (loss) income	$217.20	$154.10
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation, depletion and amortization	757.1	648.3
Deferred income taxes	39.3	54.7
Impairment	4	70.9
Share-based compensation	20	19.5
Amortization of debt issuance costs and discounts	4.7	3.7
Net gain from asset sales	-113	-1.5
Income from unconsolidated affiliates	-3.7	-5.6
Distributions from unconsolidated affiliates and other	5.9	6.1
Unrealized loss (gain) on derivative contracts	55.5	-32.8
Changes in operating assets and liabilities	-8.1	54.6
Net Cash Provided by Operating Activities	978.9	972
INVESTING ACTIVITIES	'	'
Property acquisitions	-39.3	-1,400.30
Property, plant and equipment, including dry exploratory well expense	-1,089.60	-1,040.70
Proceeds from disposition of assets	208.3	5.3
Net Cash Used in Investing Activities	-920.6	-2,435.70
FINANCING ACTIVITIES	'	'
Checks outstanding in excess of cash balances	-38.1	-1.9
Long-term debt issued	0	1,450
Long-term debt issuance costs paid	-3	-17
Long-term debt repaid	0	6.7
Proceeds from credit facility	1,075	933.5
Repayments of credit facility	-1,400	-876
Payments for Repurchase of Common Stock	-8.7	0
Proceeds from Issuance of Common Limited Partners Units	449.6	0
Other capital contributions	3.6	-4.2
Dividends paid	-10.8	-10.7
Excess tax benefit on share-based compensation	1.3	2
Distribution to noncontrolling interest	-4.2	-5.3
Net Cash Provided by Financing Activities	64.7	1,463.70
Change in cash and cash equivalents	123	0
Beginning cash and cash equivalents	0	0
Ending cash and cash equivalents	123	0
Supplemental Disclosures:	'	'
Cash paid for interest, net of capitalized interest	120.1	79.8
Cash paid (received) for income taxes	49.4	28
Non-cash investing activities	'	'
Change in capital expenditure accrual balance	$53.70	$97.50

Nature_of_Business

Nature of Business	9 Months Ended
	Sep. 30, 2013
Nature Of Business [Abstract]	'
Nature of Business	'
	Nature of Business
	QEP Resources, Inc. (QEP or the Company) is a holding company with three major lines of business: natural gas and crude oil exploration and production; midstream field services; and energy marketing. These businesses are conducted through the Company’s three principal subsidiaries:
	•	QEP Energy Company (QEP Energy) acquires, explores for, develops, and produces natural gas, oil, and natural gas liquids (NGL);
	•	QEP Field Services Company (QEP Field Services, which includes the ownership and operations of QEP Midstream Partners, LP (QEP Midstream)), provides midstream field services, including natural gas gathering, processing, compression, and treating services, for affiliates and third parties; and
	•	QEP Marketing Company (QEP Marketing) markets affiliate and third-party natural gas and oil, and owns and operates an underground gas-storage reservoir.
	QEP's operations are focused in two major regions: the Northern Region (primarily in North Dakota, Wyoming and Utah) and the Southern Region (primarily in Oklahoma, Louisiana and the Texas Panhandle) of the United States. QEP’s corporate headquarters are located in Denver, Colorado.
	Shares of QEP’s common stock trade on the New York Stock Exchange under the ticker symbol “QEP”.

Basis_of_Presentation_of_Inter

Basis of Presentation of Interim Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Presentation of Interim Consolidated Financial Statements	'
	Basis of Presentation of Interim Consolidated Financial Statements
	The interim condensed consolidated financial statements contain the accounts of QEP and its majority-owned or controlled subsidiaries, including QEP Midstream (see Note 3 - QEP Midstream). The condensed consolidated financial statements were prepared in accordance with United States Generally Accepted Accounting Principles (GAAP) and with the instructions for quarterly reports on Form 10-Q and Regulations S-X and S-K. All significant intercompany accounts and transactions have been eliminated in consolidation.
	The condensed consolidated financial statements reflect all normal recurring adjustments and accruals that are, in the opinion of management, necessary for a fair statement of financial position and results of operations for the interim periods presented. Interim condensed consolidated financial statements do not include all of the information and notes required by GAAP for audited annual consolidated financial statements. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.
	The preparation of the condensed consolidated financial statements and notes in conformity with GAAP requires that management make estimates and assumptions that affect revenues, expenses, assets and liabilities, and disclosure of contingent assets and liabilities. Actual results could differ from estimates. The results of operations for the three and nine months ended September 30, 2013, are not necessarily indicative of the results that may be expected for the year ending December 31, 2013.
	New accounting pronouncements
	In February of 2013, the FASB issued ASU 2013-02, Other Comprehensive Income (Topic 220: Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income), which seeks to improve the reporting of entities by requiring an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required under GAAP to be reclassified in its entirety to net income. For other amounts that are not required under GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under GAAP that provide additional detail about those amounts. The amendments are effective prospectively for reporting periods beginning on or after December 15, 2012. The Company adopted this standard in the first quarter of 2013 and noted that it did not have a significant impact on the Company's consolidated financial statements.
	In December of 2011, the FASB issued ASU 2011-11, Disclosures about Offsetting Assets and Liabilities, which enhances disclosure requirements regarding an entity’s financial instruments and derivative instruments that are offset or subject to a master netting arrangement. This information about offsetting and related netting arrangements will enable users of financial statements to understand the effect of those arrangements on the entity’s financial position, including the effect of rights of setoff. Additionally, the FASB issued ASU 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities, which clarifies the implementation of ASU 2011-01. The amendments are required for annual reporting periods beginning after January 1, 2013, and interim periods within those annual periods. The Company adopted this standard effective January 1, 2013. It did not have a significant impact on the Company's consolidated financial statements.
	In July of 2012, the FASB issued ASU 2012-02, Intangibles - Goodwill and Other: Testing Indefinite-Lived Intangible Assets for Impairment, which revises the way an entity can test indefinite-lived intangible assets for impairment by allowing an entity to first assess qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that the indefinite-lived intangible asset is impaired. If there is no indication of impairment from the qualitative impairment test, the entity is not required to complete a quantitative impairment test of determining and comparing the fair value with the carrying amount of the indefinite-lived asset. Under the guidance in this ASU, an entity also has the option to bypass the qualitative assessment in any period and proceed directly to performing the quantitative impairment test, while retaining the ability to resume performing the qualitative assessment in any subsequent period. The amendments are effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. The Company adopted this standard January 1, 2013, which has allowed the Company to more efficiently complete the annual goodwill impairment test but has not had a significant impact on the Company's consolidated financial statements.

QEP_Midstream_Notes

QEP Midstream (Notes)	9 Months Ended
	Sep. 30, 2013
QEP Midstream [Abstract]	'
Noncontrolling Interest Disclosure [Text Block]	'
	QEP Midstream
	QEP Midstream is a publicly traded master limited partnership that was formed by QEP to own, operate, acquire and develop midstream energy assets. QEP Midstream's assets currently consist of ownership interests in four gathering systems and two Federal Energy Regulatory Commission (FERC) regulated pipelines, which provide natural gas and crude oil gathering and transportation services. These assets are located in, or within close proximity to, the Green River Basin located in Wyoming and Colorado, the Uinta Basin located in eastern Utah, and the portion of the Williston Basin located in North Dakota.
	Initial Public Offering
	On August 14, 2013, QEP Midstream completed its initial public offering (the Offering) of 20,000,000 common units, representing limited partner interests in QEP Midstream, at a price to the public of $21.00 per common unit. QEP Midstream received net proceeds of $390.7 million from the sale of the common units, after deducting underwriting discounts and commissions, structuring fees and offering expenses of approximately $29.3 million. Following the Offering, the underwriters exercised their over-allotment option to purchase an additional 3,000,000 common units, at a price of $21.00 per common unit, providing additional net proceeds of $58.9 million, after deducting $4.1 million of underwriters' discounts and commissions and structuring fees, to QEP Midstream.
	QEP Midstream used the net proceeds to repay its outstanding debt balance with QEP, which was assumed with the assets contributed to QEP Midstream, pay revolving credit facility origination fees and make a cash distribution to QEP, a portion of which was used to reimburse QEP for certain capital expenditures it incurred with respect to assets contributed to QEP Midstream. The following table is a reconciliation of proceeds from the initial public offering (in millions):
	Total proceeds from the Offering		$	483
	Offering costs		(33.4		)
	Net proceeds from the Offering		449.6
	Revolving credit facility origination fees		(3.0		)
	Repayment of outstanding debt with QEP		(95.5		)
	Net proceeds distributed to QEP from the Offering		$	351.1
	QEP Midstream Partners GP, LLC (the General Partner), a wholly-owned subsidiary of QEP, serves as the general partner of QEP Midstream. QEP owns a 57.8% interest in QEP Midstream and consolidates QEP Midstream for financial reporting purposes with the portion not owned by QEP reflected as a reduction to net income and equity as noncontrolling interest.
	Contribution, Conveyance and Assumption Agreement
	On August 14, 2013, in connection with the closing of the Offering, QEP entered into a Contribution, Conveyance and Assumption Agreement (the Contribution Agreement) with QEP Field Services, the General Partner and QEP Midstream Partners Operating, LLC (the Operating Company). Immediately prior to the closing of the Offering, the following transactions, among others, occurred pursuant to the Contribution Agreement:
	•	QEP Field Services contributed to the General Partner, as a capital contribution, a limited liability company interest in the Operating Company with a value equal to 2.0% of the equity value of QEP Midstream at the closing of the Offering;
	•	the General Partner contributed to QEP Midstream, as a capital contribution, the limited liability company interest in the Operating Company in exchange for (a) 1,090,000 general partner units representing the continuation of an aggregate 2.0% general partner interest in QEP Midstream and (b) all the incentive distribution rights of QEP Midstream;
	•	QEP Field Services contributed to QEP Midstream, as a capital contribution, its remaining limited liability company interests in the Operating Company in exchange for (a) 6,701,750 common units representing a 12.3% limited partner interest in QEP Midstream, (b) 26,705,000 subordinated units representing a 49.0% limited partner interest in QEP Midstream and (c) the right to receive a distribution from QEP Midstream; and
	•	the public, through the underwriters, contributed $420.0 million in cash (or $390.7 million, net of the underwriters' discounts and commissions, structuring fees and offering expenses of approximately $29.3 million) to QEP Midstream in exchange for the issuance of 20,000,000 common units.
	Subsequent to the Offering, the underwriters exercised their over-allotment option to purchase an additional 3,000,000 common units in QEP Midstream, which reduced QEP's limited partner common unit interest in QEP Midstream from 12.3% to 6.8% and QEP's total ownership interest from 63.3% to 57.8%.
	Omnibus Agreement
	In connection with the Offering, QEP entered into an Omnibus Agreement (the Omnibus Agreement) with QEP Midstream on August 14, 2013, that addresses the following matters:
	•	QEP Midstream's payment of an annual amount to QEP, initially in the amount of approximately $13.8 million, for the provision of certain general and administrative services by QEP and its affiliates to QEP Midstream, including a fixed annual fee of approximately $1.4 million for providing certain executive management services by certain officers of the General Partner. The remaining portion of this annual amount reflects an estimate of the costs QEP and its affiliates expect to incur in providing the services;
	•	QEP Midstream's obligation to reimburse QEP for any out-of-pocket costs and expenses incurred by QEP in providing general and administrative services (which reimbursement is in addition to certain expenses of the General Partner and its affiliates that are reimbursed under QEP Midstream's partnership agreement), as well as any other out-of-pocket expenses incurred by QEP on QEP Midstream's behalf; and
	•	an indemnity by QEP for certain environmental and other liabilities, and QEP Midstream's obligation to indemnify QEP and its subsidiaries for events and conditions associated with the operation of QEP Midstream's assets that occur after the closing of the Offering.
	As long as QEP controls the General Partner, the Omnibus Agreement will remain in full force and effect. If QEP ceases to control the General Partner, either party may terminate the Omnibus Agreement, but the indemnification obligations will remain in full force and effect in accordance with their terms.
	Fixed Price Condensate Purchase Agreement
	On August 14, 2013, QEP entered into a fixed price Condensate Purchase Transaction Agreement (the "Condensate Purchase Agreement") with QEP Midstream. The Condensate Purchase Agreement has a primary term of five years and requires QEP Midstream to sell and QEP to purchase all of the condensate volumes collected on QEP Midstream's gathering systems at a fixed price of $85.25 per barrel.

Acquisitions_Divestitures

Acquisitions & Divestitures	9 Months Ended
	Sep. 30, 2013
Acquisitions [Abstract]	'
Acquisitions [Text Block]	'
	Acquisition and Divestitures
	Acquisitions
	On September 27, 2012, QEP Energy completed an acquisition of oil and gas properties in the Williston Basin for an aggregate purchase price of $1.4 billion (the 2012 Acquisition). The properties are located in Williams and McKenzie counties of North Dakota, approximately 12 miles west of QEP's then-existing core acreage in the Williston Basin.
	The 2012 Acquisition meets the definition of a business combination under ASC 805, Business Combinations, as it included proved properties. QEP allocated the cost of the 2012 Acquisition to assets acquired and liabilities assumed based on fair values as of the acquisition date. Revenues of $76.0 million and $190.1 million and net income of $19.2 million and $42.5 million were generated from the acquired properties during the three and nine months ended September 30, 2013, respectively, and are included in QEP's Condensed Consolidated Statements of Operations.
	QEP Energy recorded the 2012 Acquisition on its Condensed Consolidated Balance Sheet. The following table presents a summary of the Company's purchase accounting entries:
		As of September, 2013
		(in millions)
	Consideration given:
	Cash consideration	$	1,392.70
	Amounts recognized for fair value of assets acquired and liabilities assumed:
	Proved properties	$	713.8
	Unproved properties	683.4
	Asset retirement obligations	(0.9		)
	Liabilities assumed	(4.4		)
	Other assets	0.8
	Total fair value	$	1,392.70
	The following unaudited, pro forma results of operations are provided for the three and nine months ended September 30, 2012. These supplemental pro forma results of operations are provided for illustrative purposes only and may not be indicative of the actual results that would have been achieved by the acquired properties for the period presented or that may be achieved by such properties in the future. Future results may vary significantly from the results reflected in this pro forma financial information because of future events and transactions, as well as other factors. The pro forma information is based on QEP's consolidated results of operations for the three and nine months ended September 30, 2012, on the acquired properties' historical results of operations and on estimates of the effect of the transaction on the combined results. The pro forma results of operations have been prepared by adjusting the historical results of QEP to include the historical results of the acquired properties based on information provided by the seller and the impact of the purchase price allocation. The pro forma results of operations do not include any cost savings or other synergies that may result from the 2012 Acquisition or any estimated costs that have been or will be incurred by the Company to integrate the acquired properties.
		Three Months Ended					Nine Months Ended
		30-Sep-12					30-Sep-12
		Actual			Pro forma		Actual		Pro forma
		(in millions, except per share data)
	Revenues	$	542.4		$	598.9	$	1,644.90	$	1,780.40
	Net income attributable to QEP	(3.1		)	4.8		151.4		164.9
	Earnings per common share attributable to QEP
	Basic	$	(0.02	)	$	0.03	$	0.85	$	0.93
	Diluted	(0.02		)	0.03		0.85		0.93
	Divestitures
	In June 2013, QEP Energy sold its interests in several non-core oil and gas properties located in QEP's Northern Region for total cash proceeds of $140.2 million and recorded a pre-tax gain on sale of $97.4 million. In September 2013, QEP Energy sold its interests in several non-core properties located in QEP's Southern Region for total cash proceeds of $68.8 million and recorded a pre-tax gain on sale of $17.5 million. Both the cash proceeds and gains on sales are subject to post-closing adjustments. During the quarter and nine months ended September 30, 2013, QEP Energy recorded these gains on its Condensed Consolidated Statement of Operation in "Net gain from asset sales".

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings Per Share
	Basic earnings per share (EPS) are computed by dividing net income attributable to QEP by the weighted-average number of common shares outstanding during the reporting period. Diluted EPS includes the potential increase in the number of outstanding shares that could result from the exercise of in-the-money stock options. QEP’s unvested restricted shares are included in weighted-average basic common shares outstanding because once the shares are granted, the restricted shares are considered issued and outstanding, the historical forfeiture rate is minimal and the restricted shares receive dividends.
	Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents are considered participating securities and are included in the computation of earnings per share pursuant to the two-class method. The Company’s unvested restricted stock awards contain non-forfeitable dividend rights and participate equally with common stock with respect to dividends issued or declared. However, the Company’s unvested restricted stock does not have a contractual obligation to share in losses of the Company. The Company’s unexercised stock options do not contain rights to dividends. Under the two-class method, the earnings used to determine basic earnings per common share are reduced by an amount allocated to participating securities. When the Company records a net loss, none of the loss is allocated to the participating securities since the securities are not obligated to share in Company losses. Use of the two-class method has an insignificant impact on the calculation of basic and diluted earnings per common share. There were no anti-dilutive shares during the three and nine months ended September 30, 2013, or during the nine months ended September 30, 2012. During the three months ended September 30, 2012, 0.8 million shares were not included in diluted common shares outstanding as they were anti-dilutive due to QEP's net loss.
	A reconciliation of the components of basic and diluted shares used in the EPS calculation follows:
		Three Months Ended		Nine Months Ended
		September 30,		September 30,
		2013	2012	2013	2012
		(in millions)
	Weighted-average basic common shares outstanding	179.3	177.9	179.2	177.6
	Potential number of shares issuable upon exercise of in-the-money stock options under the Long-term Stock Incentive Plan	0.2	—	0.2	1
	Average diluted common shares outstanding	179.5	177.9	179.4	178.6

Asset_Retirement_Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]	'
Asset Retirement Obligations	'
	Asset Retirement Obligations
	QEP records asset retirement obligations (ARO) when there are legal obligations associated with the retirement of tangible long-lived assets. The Company’s ARO liability applies primarily to abandonment costs associated with oil and gas wells, production facilities, midstream assets and certain other properties. The fair values of such costs are estimated by Company personnel based on abandonment costs of similar assets and depreciated over the life of the related assets. Revisions to ARO estimates result from changes in expected cash flows or material changes in estimated asset retirement costs. The ARO liability is adjusted to present value each period through an accretion calculation using a credit-adjusted risk-free interest rate.
	The following is a reconciliation of the changes in the Company's asset retirement obligation from January 1, 2013, to September 30, 2013:
		Asset Retirement Obligations
		2013
		(in millions)
	ARO liability at January 1,	$	193.1
	Accretion	7.2
	Liabilities incurred	8.7
	Revisions	(25.3		)
	Liabilities settled	(13.5		)
	ARO liability at September 30,	$	170.2

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	QEP measures and discloses fair values in accordance with the provisions of ASC 820 “Fair Value Measurements and Disclosures”. This guidance defines fair value in applying GAAP, establishes a framework for measuring fair value and expands disclosures about fair-value measurements, but does not change existing guidance as to whether or not an instrument is carried at fair value. ASC 820 also establishes a fair-value hierarchy. Level 1 inputs are quoted prices (unadjusted) for identical assets or liabilities in active markets that the Company has the ability to access at the measurement date. Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability.
	QEP has determined its commodity derivative instruments are Level 2. The Level 2 fair value of commodity derivative contracts (see Note 8 - Derivative Contracts) is based on market prices posted on the respective commodity exchanges on the last trading day of the reporting period and industry standard discounted cash flow models. QEP primarily applies the market approach for recurring fair value measurements and maximizes its use of observable inputs and minimizes its use of unobservable inputs. QEP considers bid and ask prices for valuing the majority of its assets and liabilities measured and reported at fair value. In addition to using market data, QEP makes assumptions in valuing its assets and liabilities, including assumptions about risk and the risks inherent in the inputs to the valuation technique. The Company’s policy is to recognize significant transfers between Levels at the end of the reporting period.
	However, certain of the Company's commodity derivative instruments are valued using industry standard models that consider various inputs, including quoted forward prices for commodities, time value, volatility, and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these inputs are observable in the marketplace throughout the full term of the instrument and can be derived from observable data or are supported by observable prices at which transactions are executed in the marketplace. The determination of fair value for derivative assets and liabilities also incorporates nonperformance risk for counterparties and for QEP. Derivative contract fair values are reported on a net basis to the extent a legal right of offset with the counterparty exists.
	In addition, QEP has interest rate swaps that it has determined are Level 2 financial instruments. The fair values of the interest rate swaps are determined using the market standard methodology of discounting the future expected cash flows that would occur under the contractual terms of the swap. The variable interest rates used in the calculation of projected cash flows are based on an expectation of future interest rates derived from observable market interest rate curves. QEP incorporates credit valuation adjustments to reflect both its nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. While the credit valuation adjustments are not observable inputs, they are not significant to the overall valuation and the other inputs used to value the interest rate swaps are observable Level 2 inputs.
	The fair value of financial assets and liabilities at September 30, 2013, is shown in the table below:
		Fair Value Measurements
		30-Sep-13
		Gross Amounts of Assets and Liabilities						Netting			Net Amounts Presented on the Condensed Consolidated Balance Sheet
		Level 1		Level 2		Level 3		Adjustments(1)
		(in millions)
	Financial Assets
	Commodity derivative instruments - short-term	$	—	$	58	$	—	$	(18.6	)	$	39.4
	Commodity derivative instruments - long-term	—		5.8		—		—			5.8
	Total financial assets	$	—	$	63.8	$	—	$	(18.6	)	$	45.2
	Financial Liabilities
	Commodity derivative instruments - short-term	$	—	$	26.2	$	—	$	(18.6	)	$	7.6
	Interest rate swaps - short-term	—		2.5		—		—			2.5
	Total financial liabilities	$	—	$	28.7	$	—	$	(18.6	)	$	10.1
	____________________________
	(1) The Company nets its derivative contract assets and liabilities outstanding with the same counterparty on the Condensed Consolidated Balance Sheet as the contracts contain netting provisions. Refer to Note 8 - Derivative Contracts, for additional information regarding the Company's derivative contracts.
	The fair value of financial assets and liabilities at December 31, 2012, is shown in the table below:
		Fair Value Measurements
		31-Dec-12
		Gross Amounts of Assets and Liabilities						Netting			Net Amounts Presented on the Condensed Consolidated Balance Sheet
		Level 1		Level 2		Level 3		Adjustments(1)
		(in millions)
	Financial Assets
	Commodity derivative instruments - short-term	$	—	$	189.7	$	—	$	(1.0	)	$	188.7
	Commodity derivative instruments - long-term	—		4.2		—		(0.1		)	4.1
	Total financial assets	$	—	$	193.9	$	—	$	(1.1	)	$	192.8
	Financial Liabilities
	Commodity derivative instruments - short-term	$	—	$	1	$	—	$	(1.0	)	$	—
	Interest rate swaps - short-term	—		2.6		—		—			2.6
	Commodity derivative instruments - long-term	—		0.1		—		(0.1		)	—
	Interest rate swaps - long-term	—		3.6		—		—			3.6
	Total financial liabilities	$	—	$	7.3	$	—	$	(1.1	)	$	6.2
	_______________________
	(1) The Company nets its derivative contract assets and liabilities outstanding with the same counterparty on the Condensed Consolidated Balance Sheet as the contracts contain netting provisions. Refer to Note 8 - Derivative Contracts, for additional information regarding the Company's derivative contracts.
	The following table discloses the fair value and related carrying amount of certain financial instruments not disclosed in other notes to the condensed consolidated financial statements in this quarterly report on Form 10-Q:
		Carrying		Level 1		Carrying		Level 1
		Amount		Fair Value		Amount		Fair Value
		September 30, 2013				December 31, 2012
		(in millions)
	Financial assets
	Cash and cash equivalents	$	123	$	123	$	—	$	—
	Financial liabilities
	Checks outstanding in excess of cash balances	$	1.6	$	1.6	$	39.7	$	39.7
	Long-term debt	$	2,882.30	$	2,900.50	$	3,206.90	$	3,420.70
	The carrying amounts of cash and cash equivalents and checks outstanding in excess of cash balances approximate fair value. The fair value of fixed-rate long-term debt is based on the trading levels and dollar prices for the Company’s debt at the end of the quarter. The carrying amount of variable-rate long-term debt approximates fair value because the floating interest rate paid on such debt was set for periods of one month.
	The initial measurement of asset retirement obligations at fair value is calculated using discounted cash flow techniques and based on internal estimates of future retirement costs associated with property, plant and equipment. Significant Level 3 inputs used in the calculation of asset retirement obligations include plugging costs and remaining reserve lives. A reconciliation of the Company’s asset retirement obligations is presented in Note 6 – Asset Retirement Obligations.

Derivative_Contracts

Derivative Contracts	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Contracts	'
	Derivative Contracts
	QEP has established policies and procedures for managing commodity price volatility through the use of derivative instruments. In the normal course of business, QEP uses commodity price derivative instruments to reduce the impact of potential downward movements in commodity prices on cash flow, returns on capital investment, and other financial results. However, these instruments typically limit gains from favorable price movements. The volume of production subject to commodity derivative instruments and the mix of the instruments are frequently evaluated and adjusted by management in response to changing market conditions. QEP may enter into commodity derivative contracts for up to 100% of forecasted production from proved reserves. In addition, QEP may enter into commodity derivative contracts on a portion of its extracted NGL volumes in its midstream business and a portion of its natural gas sales and purchases for marketing transactions. QEP does not enter into commodity derivative instruments for speculative purposes.
	QEP uses commodity derivative instruments known as fixed-price swaps to realize a known price for a specific volume of production delivered into a regional sales point. QEP’s commodity derivative instruments do not require the physical delivery of natural gas, crude oil, or NGL between the parties at settlement. Swap transactions are settled in cash with one party paying the other for the net difference in prices, multiplied by the contract volume, for the settlement periods. Natural gas price derivative instruments are typically structured as fixed-price swaps at regional price indices. Oil price derivative instruments are typically structured as NYMEX fixed-price swaps based at Cushing, Oklahoma. QEP also has oil price derivative fixed-price swaps that use Brent crude oil prices as the reference price. Brent crude oil contracts are traded on the IntercontinentalExchange, Inc. (ICE). NGL price derivative instruments are typically structured as Mont Belvieu, Texas fixed-price swaps.
	QEP enters into commodity derivative transactions that do not have margin requirements or collateral provisions that would require payments prior to the scheduled settlement dates. Commodity derivative contract counterparties are normally financial institutions and energy trading firms with investment-grade credit ratings. QEP routinely monitors and manages its exposure to counterparty risk by requiring specific minimum credit standards for all counterparties and avoids concentration of credit exposure by transacting with multiple counterparties.
	Effective January 1, 2012, QEP elected to de-designate all of its natural gas, crude oil and NGL derivative contracts that were previously designated as cash flow hedges and discontinue hedge accounting prospectively. As a result of discontinuing hedge accounting, the mark-to-market values at December 31, 2011, were fixed in Accumulated Other Comprehensive Income (AOCI) as of the de-designation date and are being reclassified into the Condensed Consolidated Statement of Operations as the transactions settle and affect earnings. At September 30, 2013, AOCI included $27.3 million ($17.2 million after tax) of unrealized gains that will be settled and reclassified from AOCI to the Condensed Consolidated Statements of Operations during the remainder of 2013. During the nine months ended September 30, 2013 and 2012, $60.4 million and $133.8 million, respectively, of unrealized gains, after tax, were reclassified from AOCI into the Condensed Consolidated Statement of Operations in "Realized and unrealized (losses) gains on derivative contracts" as the transactions settled. QEP expects to reclassify into earnings from AOCI the fixed value related to de-designated natural gas, oil and NGL derivatives over the remainder of 2013. Currently, QEP recognizes all gains and losses from changes in the fair value of natural gas, oil and NGL derivative contracts immediately in earnings rather than deferring any such amounts in AOCI. All commodity derivative instruments are recorded on the Condensed Consolidated Balance Sheets as either assets or liabilities measured at their fair values and all realized and unrealized gains and losses from derivative instruments incurred after January 1, 2012, are presented in the Condensed Consolidated Statement of Operations in “Realized and unrealized (losses) gains on derivative contracts” below operating income.
	QEP also uses interest rate swaps to mitigate a portion of its exposure to interest rate volatility risk. During the second quarter of 2012, QEP entered into variable-to-fixed interest rate swap agreements having a combined notional principal amount of $300.0 million to minimize the interest rate volatility risk associated with its $300.0 million senior, unsecured term loan. QEP locked in a fixed interest rate of 1.07% in exchange for a variable interest rate indexed to the one-month LIBOR rate. The interest rate swaps settle monthly and will mature in March of 2017.
	QEP Energy Derivative Contracts
	The following table sets forth QEP Energy’s quantities and average prices for its commodity derivative contracts as of September 30, 2013:
	Insert Title Here
	Year		Type of Contract		Index	Total			Average Swap price per unit
						Volumes
						(in millions)
	Natural gas					(MMBtu)
	2013		Swap		IFNPCR(1)	18.4			$	5.49
	2013		Swap		NYMEX	14.7			$	3.81
	2014		Swap		IFNPCR(1)	32.9			$	4
	2014		Swap		NYMEX	25.6			$	4.19
	Crude oil					(Bbls)
	2013		Swap		NYMEX WTI	2.1			$	98.27
	2013		Swap		BRENT ICE	0.1			$	107.8
	2014		Swap		NYMEX WTI	8.8			$	93.63
	(1)	Inside FERC monthly settlement index for the Northwest Pipeline Corp. Rocky Mountains.
	QEP Marketing Derivative Contracts
	QEP Marketing enters into commodity derivative transactions to lock in a margin on natural gas volumes placed into storage and for marketing transactions in which QEP Marketing sells gas volumes at a fixed price. The following table sets forth QEP Marketing’s volumes and swap prices for its commodity derivative contracts as of September 30, 2013:
	Year		Type of Contract		Index	Total			Average Swap price
						Volumes			per MMBtu
						(in millions)
	Natural gas sales					(MMBtu)
	2013		Swap		IFNPCR	1.6			$	3.91
	2014		Swap		IFNPCR	3.8			$	3.71
	Natural gas purchases					(MMBtu)
	2013		Swap		IFNPCR	1.7			$	3.46
	2014		Swap		IFNPCR	0.2			$	3.82
	QEP's Derivative Contracts
	The following table sets forth QEP’s notional amount and interest rate for its interest rate swaps outstanding as of September 30, 2013:
	Notional amount		Type of Contract		Maturity	Fixed Rate Paid		Variable Rate Received
	(in millions)
	$300.00		Swap		Mar-17	1.07%		One month LIBOR
	QEP Derivative Financial Statement Presentation
	The following table identifies the balance sheet location of QEP’s outstanding derivative contracts on a gross contract basis as opposed to the net contract basis presentation in the Condensed Consolidated Balance Sheets and the related fair values at the balance sheet dates:
				Gross asset derivative							Gross liability derivative
				instruments fair value							instruments fair value
		Balance Sheet		September 30,			31-Dec-12				September 30,			31-Dec-12
		line item		2013							2013
				(in millions)							(in millions)
	Current:
	Commodity	Fair value of derivative contracts		$	58		$	189.7			$	26.2		$	1
	Interest rate swaps	Fair value of derivative contracts		—			—				2.5			2.6
	Long-term:
	Commodity	Fair value of derivative contracts		5.8			4.2				—			0.1
	Interest rate swaps	Fair value of derivative contracts		—			—				—			3.6
	Total derivative instruments			$	63.8		$	193.9			$	28.7		$	7.3
	The effects of the change in fair value and settlement of QEP's derivative contracts recorded in "Realized and unrealized (losses) gains on derivative contracts" on the Condensed Consolidated Statements of Operations are summarized in the following tables:
			Three Months Ended							Nine Months Ended
	Derivative instruments not designated as cash flow hedges		September 30,							September 30,
			2013			2012				2013			2012
	Realized gains (losses) on commodity derivative contracts		(in millions)
	QEP Energy
	Natural gas derivative contracts		$	42.5		$	86.2			$	112		$	283.8
	Oil derivative contracts		(15.3		)	2.7				(3.7		)	2.2
	NGL derivative contracts		—			3.4				—			6.5
	QEP Field Services
	NGL derivative contracts		—			1.9				—			6.3
QEP Marketing
Natural gas derivative contracts		(0.3		)	(0.4		)		0.7			3.7
Total realized gains on commodity derivative contracts		26.9			93.8				109			302.5
Unrealized gains (losses) on commodity derivative contracts
QEP Energy
Natural gas derivative contracts		(6.6		)	(50.6		)		(9.6		)	3.3
Oil derivative contracts		(46.2		)	4.1				(49.1		)	31.2
NGL derivative contracts		—			(4.4		)		—			3.4
QEP Field Services
NGL derivative contracts		—			(2.5		)		—			2
QEP Marketing
Natural gas derivative contracts		0.1			(1.4		)		(0.3		)	(0.5		)
Total unrealized (losses) gains on commodity derivative contracts		(52.7		)	(54.8		)		(59.0		)	39.4
Total realized and unrealized (losses) gains on commodity derivative contracts		$	(25.8	)	$	39			$	50		$	341.9
Realized gains (losses) on interest rate swaps
Realized losses on interest rate swaps		$	(0.6	)	$	(0.6	)		$	(1.9	)	$	(0.6	)
Unrealized gains (losses) on interest rate swaps
Unrealized (losses) gains on interest rate swaps		(1.4		)	(2.3		)		3.5			(6.6		)
Total realized and unrealized (losses) gains on interest rate swaps		$	(2.0	)	$	(2.9	)		$	1.6		$	(7.2	)
Total net realized gains on derivative contracts		$	26.3		$	93.2			$	107.1		$	301.9
Total net unrealized (losses) gains on derivative contracts		(54.1		)	(57.1		)		(55.5		)	32.8
Grand Total		$	(27.8	)	$	36.1			$	51.6		$	334.7

Restructuring_Costs

Restructuring Costs	9 Months Ended
	Sep. 30, 2013
Restructuring Costs [Abstract]	'
Restructuring Costs	'
	Restructuring Costs
	During the first quarter of 2012, QEP began incurring costs related to the closure of its Oklahoma City office and the subsequent consolidation of its Southern Region operations into a single regional office located in Tulsa. During the second half of 2012, QEP incurred additional restructuring and reorganization costs related to consolidating various corporate and accounting functions to the Denver corporate headquarters. The creation of one office for QEP’s Southern Region as well as the consolidation of corporate and accounting functions was intended to increase efficiency, team-based collaboration and organizational productivity over the long term. As part of the reorganization, QEP incurred costs associated with the severance, retention and relocation of employees, additional pension expenses, exit costs associated with the termination of operating leases arising from office space that will no longer be utilized by the Company and other expenses. The Company currently estimates that the remaining restructuring costs will be incurred during the remainder of 2013.
	The following table summarizes, by line of business, each major type of cost expected to be incurred and the total amounts recorded in "General and administrative" expense on the Condensed Consolidated Statement of Operations for the respective periods indicated:
		Total Restructuring Costs
		Total Expected to be Incurred			Recognized in Income
					Period from Inception to September 30, 2013			Three Months Ended September 30, 2013						Nine Months Ended September 30, 2013
								2013			2012			2013		2012
	QEP Energy	(in millions)
	One-time termination benefits	$	3.3		$	3.3		$	0.1		$	0.2		0.4		2.1
	Retention & relocation expense	3.7			3.6			0.1			0.1			0.3		3.2
	Lease termination costs	0.6			0.6			—			—			—		—
	Total restructuring costs	$	7.6		$	7.5		$	0.2		$	0.3		0.7		5.3
	QEP Field Services
	One-time termination benefits	$	—		$	—		$	—		$	—		—		—
	Retention & relocation expense	0.1			0.1			0.1			—			0.1		—
	Lease termination costs	—			—			—			—			—		—
	Total restructuring costs	$	0.1		$	0.1		$	0.1		$	—		0.1		—
	QEP Marketing
	One-time termination benefits	$	0.3		$	0.3		$	—		$	—		0.1		—
	Retention & relocation expense	—			—			—			—			—		—
	Lease termination costs	—			—			—			—			—		—
	Total restructuring costs	$	0.3		$	0.3		$	—		$	—		0.1		—
	Total QEP
	One-time termination benefits	$	3.6		$	3.6		$	0.1		$	0.2		$	0.5	$	2.1
	Retention & relocation expense	3.8			3.7			0.2			0.1			0.4		3.2
	Lease termination costs	0.6			0.6			—			—			—		—
	Total restructuring costs	$	8		$	7.9		$	0.3		$	0.3		$	0.9	$	5.3
	The following is a reconciliation of the restructuring liability, by line of business, which is included within “Accounts payable and accrued expenses” on the Condensed Consolidated Balance Sheets:
		QEP Energy			QEP Field Services			QEP Marketing			Total
		(in millions)
	Balance at December 31, 2012	$	1		$	—		$	—		$	1
	Costs incurred and charged to expense	0.7			0.1			0.1			0.9
	Costs paid or otherwise settled	(1.7		)	(0.1		)	(0.1		)	(1.9		)
	Balance at September 30, 2013	$	—		—			—			$	—

Debt

Debt	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Debt	'
	Debt
	As of the indicated dates, the principal amount of QEP’s debt, including amounts outstanding under its and QEP Midstream's revolving credit facilities, QEP's term loan and QEP's senior notes consisted of the following:
		September 30,			December 31,
		2013			2012
		(in millions)
	QEP's revolving credit facility due 2016	$	365		$	690
	QEP Midstream's revolving credit facility due 2018	—			—
	Term loan due 2017	300			300
	6.05% Senior Notes due 2016	176.8			176.8
	6.80% Senior Notes due 2018	134			134
	6.80% Senior Notes due 2020	136			136
	6.875% Senior Notes due 2021	625			625
	5.375% Senior Notes due 2022	500			500
	5.25% Senior Notes due 2023	650			650
	Total principal amount of debt	2,886.80			3,211.80
	Less unamortized discount	(4.5		)	(4.9		)
	Total long-term debt outstanding	$	2,882.30		$	3,206.90
	Of the total debt outstanding on September 30, 2013, amounts outstanding under QEP's revolving credit facility due August 25, 2016, QEP Midstream's revolving credit facility due August 14, 2018, QEP's term loan due April 18, 2017, the 6.05% Senior Notes due September 1, 2016, and the 6.80% Senior Notes due April 1, 2018, will mature within the next five years.
	Credit Facilities
	QEP's Credit Facility
	QEP’s revolving credit facility, which matures in August 2016, provides for loan commitments of $1.5 billion from a group of financial institutions. The credit facility provides for borrowing at short-term interest rates and contains customary covenants and restrictions. The credit facility also contains an accordion provision that would allow for the amount of the facility to be increased to $2.0 billion and for the maturity to be extended for up to two additional one-year periods, with the agreement of the lenders.
	During the nine months ended September 30, 2013 and 2012, QEP’s weighted-average interest rate on borrowings from its credit facility was 2.56% and 2.05%, respectively. At September 30, 2013 and December 31, 2012, QEP was in compliance with the covenants under the credit agreement. At September 30, 2013, there was $365.0 million outstanding and $3.7 million of letters of credit issued under the credit facility.
	QEP Midstream's Credit Facility
	On August 14, 2013, QEP Midstream entered into a $500.0 million senior secured revolving credit facility with a group of financial institutions, which matures on August 14, 2018. QEP Midstream's credit facility contains an accordion provision that allows for the amount of the facility to be increased to $750.0 million with the agreement of the lenders. QEP Midstream's credit facility is available for QEP Midstream's working capital, capital expenditures, permitted acquisitions and general corporate purposes, including distributions. Substantially all of QEP Midstream's assets, excluding equity in and assets of certain joint ventures and unrestricted subsidiaries, are pledged as collateral under the credit facility. In addition, the credit facility contains restrictions and events of default customary for agreements of this nature.
	There have been no borrowings under QEP Midstream's credit facility, and at September 30, 2013, QEP Midstream was in compliance with the covenants under the QEP Midstream credit facility agreement.
	QEP is not a borrower or guarantor of QEP Midstream's credit facility. In addition, QEP is not subject to any of the restrictions or covenants contained in QEP Midstream's credit agreement. Outstanding indebtedness under QEP Midstream's credit facility is not included in the definition of indebtedness under QEP's credit facility.
	Term Loan
	QEP's $300.0 million term loan facility provides for borrowings at short-term interest rates and contains covenants, restrictions and interest rates that are substantially the same as QEP’s revolving credit facility. The term loan matures in April 2017, and the maturity date may be extended one year with the agreement of the lenders. During the nine months ended September 30, 2013 and 2012, QEP’s weighted-average interest rate on borrowings from the term loan was 2.23% and 2.02%, respectively. At September 30, 2013 and December 31, 2012, QEP was in compliance with the covenants under the term loan credit agreement.
	Senior Notes
	At September 30, 2013, the Company had $2,221.8 million principal amount of senior notes outstanding with maturities ranging from September 2016 to May 2023 and coupons ranging from 5.25% to 6.875%. The senior notes pay interest semi-annually, are unsecured senior obligations and rank equally with all of our other existing and future unsecured and senior obligations. QEP may redeem some or all of its senior notes at any time before their maturity at a redemption price based on a make-whole amount plus accrued and unpaid interest to the date of redemption. The indentures governing QEP’s senior notes contain customary events of default and covenants that may limit QEP’s ability to, among other things, place liens on its property or assets.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Contingencies	'
	Contingencies
	QEP is involved in various commercial and regulatory claims, litigation and other legal proceedings that arise in the ordinary course of its business. QEP assesses these claims in an effort to determine the degree of probability and range of possible loss for potential accrual in its consolidated financial statements. In accordance with ASC 450, Contingencies, an accrual is recorded for a loss contingency when its occurrence is probable and damages can be reasonably estimated based on the anticipated most likely outcome or the minimum amount within a range of possible outcomes. Because legal proceedings are inherently unpredictable and unfavorable resolutions could occur, assessing contingencies is highly subjective and requires judgments about uncertain future events. When evaluating contingencies, QEP may be unable to provide a meaningful estimate due to a number of factors, including the procedural status of the matter in question, the presence of complex or novel legal theories, and/or the ongoing discovery and development of information important to the matter. QEP's litigation loss contingencies are discussed below. QEP is unable to estimate reasonably possible losses in excess of recorded accruals for these contingencies for the reasons set forth above. QEP believes, however, that the resolution of pending proceedings will not have a material effect on QEP's consolidated financial position, results of operations or cash flows.
	Environmental Claims
	In October 2009, QEP received a cease and desist order from the U.S. Army Corps of Engineers (COE) to refrain from unpermitted work resulting in the discharge of dredged and/or fill material into waters of the United States at three sites located in Caddo and Red River Parishes, Louisiana. Region 6 of the U.S. Environmental Protection Agency (EPA) has assumed lead responsibility for enforcement of the cease and desist order and any possible future orders for the removal of unauthorized fills and/or civil penalties under the Clean Water Act. On June 28, 2013, the EPA issued to QEP an Administrative Complaint for the alleged violations. QEP and the EPA reached an agreement to settle the alleged violations through an Administrative Order, under the terms of which QEP paid an administrative penalty of $0.2 million. The Administrative Order is final. In 2012, QEP completed a field audit, which identified 112 additional instances affecting approximately 90 acres where work may have been conducted in violation of the Clean Water Act. QEP has disclosed each of these instances to the EPA under the EPA's Audit Policy (to reduce penalties) and to the COE. QEP is working with the EPA and the COE to resolve these matters, which will require the Company to undertake certain mitigation and permitting activities, and may require QEP to pay a monetary penalty.
	In July 2010, QEP received a Notice of Potential Penalty (NOPP) from the Louisiana Department of Environmental Quality (LDEQ) regarding the assumption of ownership and operatorship of a single facility in Louisiana prior to transferring the facility's air quality permit. In 2011, QEP completed an internal audit, which identified 424 facilities in Louisiana for which QEP both failed to submit a complete permit application and to receive approval from the department prior to construction, modification, or operation. QEP has corrected and disclosed all instances of non-compliance to the LDEQ and is working with the department to resolve the NOPP. The LDEQ has assumed lead responsibility for enforcement of the NOPP and may require the Company to pay a monetary penalty.
	Litigation
	Chieftain Royalty Company v. QEP Energy Company, Case No CIV-11-0212-R, U. S. District Court for the Western District of Oklahoma. This statewide class action was filed in January 2011 on behalf of QEP's Oklahoma royalty owners asserting various claims for damages related to royalty valuation on all of QEP's Oklahoma wells operated by QEP or from which QEP marketed gas. These claims include breach of contract, breach of fiduciary duty, fraud, unjust enrichment, tortious breach of contract, conspiracy, and conversion, based generally on asserted improper deduction of post-production costs. The Court certified the class as to the breach of contract, breach of fiduciary duty and unjust enrichment claims. The parties successfully mediated the case in January 2013. On February 13, 2013, the parties executed a Stipulation and Agreement of Settlement (the Chieftain Settlement Agreement) providing for a cash payment from QEP to the class in the amount of $115.0 million. In consideration for the settlement payment, QEP received a full release of all claims regarding the calculation, reporting and payment of royalties from the sale of natural gas and its constituents for all periods prior to February 28, 2013, and all class members are enjoined from asserting claims related to such royalties. As part of the Chieftain Settlement Agreement, the parties also agreed on the methodology for the calculation and payment of future royalties payable by QEP, or its successors and assigns, under all class leases for the life of such leases. On May 31, 2013, the Court issued its order approving the settlement, which is now final.
	Questar Gas Company v. QEP Field Services Company, Civil No. 120902969, Third Judicial District Court, State of Utah. At the closing of the Offering, the assets and agreement discussed below were assigned to QEP Midstream. QEP Field Services' former affiliate, Questar Gas Company (QGC), filed this complaint in state court in Utah on May 1, 2012, asserting claims for (i) breach of contract, (ii) breach of implied covenant of good faith and fair dealing, (iii) an accounting and (iv) declaratory judgment related to a 1993 gathering agreement (the 1993 Agreement) executed when the parties were affiliates. Under the 1993 Agreement, certain of QEP Field Services' systems provide gathering services to QGC charging an annual gathering rate which is based on cost of service. QGC is disputing the annual calculation of the gathering rate. The annual gathering rate has been calculated in the same manner under the 1993 Agreement since it was amended in 1998, without any prior objection or challenge by QGC. QGC was netting the disputed amount from its monthly payments of the gathering fees to QEP Field Services and has continued to net such amounts from its monthly payment to QEP Midstream. As of September 30, 2013, QEP Midstream has deferred revenue of $7.0 million related to the QGC disputed amount. Specific monetary damages are not asserted. QEP Field Services has filed counterclaims seeking damages and a declaratory judgment relating to its gathering services under the 1993 Agreement. QGC may seek to amend its complaint to add QEP Midstream as a defendant in the litigation. QEP Midstream has been indemnified by QEP for costs, expenses and other losses incurred by QEP Midstream in connection with the QGC dispute, subject to certain limitations, as set forth in the Omnibus Agreement (defined below in "Note 3 - QEP Midstream").

ShareBased_Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Share-Based Compensation	'
	Share-Based Compensation
	QEP issues stock options and restricted shares under its Long-Term Stock Incentive Plan (LTSIP) and awards performance-based share units under its Cash Incentive Plan (CIP) to certain officers, employees, and non-employee directors. QEP recognizes expense over time as the stock options, restricted shares, and performance-based share units vest. Deferred share-based compensation is included in additional paid-in capital in the Condensed Consolidated Balance Sheets. There were 11.9 million shares available for future grants under the LTSIP at September 30, 2013. Share-based compensation expense is recognized in “General and administrative” on the Condensed Consolidated Statements of Operations. During the three and nine months ended September 30, 2013, QEP recognized $6.8 million and $20.0 million, respectively, in total compensation expense related to share-based compensation compared to $7.2 million and $19.5 million during the three and nine months ended September 30, 2012, respectively.
	QEP Midstream maintains a unit-based compensation plan for officers, directors and employees of the general partner of QEP Midstream and its affiliates and any consultants, affiliates of the general partner, or other individuals who perform services for QEP Midstream. The QEP Midstream 2013 Long-Term Incentive Plan (the QEP Midstream LTIP) permits various types of awards, including awards of restricted units, phantom units, unit options, unit appreciation rights, distribution equivalent rights, profits interest units and other unit-based awards. Awards granted during 2013 under the QEP Midstream LTIP will be settled with QEP Midstream units. During the three and nine months ended September 30, 2013, QEP recognized $0.1 million in compensation expense related to QEP Midstream LTIP.
	Stock Options
	QEP uses the Black-Scholes-Merton mathematical model to estimate the fair value of stock option awards at the date of the grant. Fair-value calculations rely upon subjective assumptions used in the mathematical model and may not be representative of future results. The Black-Scholes-Merton model is intended for measuring the value of options traded on an exchange. The Company utilizes the "simplified" method to estimate the expected term of the stock options granted as there is limited historical exercise data available in estimating the expected term of the stock options. QEP uses a historical volatility method to estimate the fair value of stock option awards and the risk-free interest rate is based on the yield on U.S. Treasury strips with maturities similar to those of the expected term of the stock options. The stock options typically vest in equal installments over a three-year period from the grant date and are exercisable immediately upon vesting through the seventh anniversary of the grant date.
	The calculated fair value of options granted and major assumptions used in the model at the date of grant are listed below:
		Stock Option Assumptions
		Nine Months Ended
		30-Sep-13
	Weighted-average grant-date fair value of awards granted during the period	$	15.16
	Weighted-average risk-free interest rate	1		%
	Weighted-average expected price volatility	58.3		%
	Expected dividend yield	0.27		%
	Expected term in years at the date of grant	5.5
	Stock option transactions under the terms of the LTSIP are summarized below:
		Options			Weighted-		Weighted-Average	Aggregate
		Outstanding			Average Exercise Price		Remaining	Intrinsic Value
							Contractual Term
					(per share)		(in years)	(in millions)
	Outstanding at December 31, 2012	1,697,471			$	25.23
	Granted	330,592			30.06
	Exercised	(209,500	)		9.6
	Forfeited	—			—
	Outstanding at September 30, 2013	1,818,563			$	27.9	3.9	$	3.6
	Options Exercisable at September 30, 2013	1,236,211			$	26.36	3	$	3.6
	Unvested Options at September 30, 2013	582,352			$	31.18	5.9	$	—
	The total intrinsic value (the difference between the market price at the exercise date and the exercise price) of options exercised was $4.2 million and $7.1 million during the nine months ended September 30, 2013 and 2012, respectively. The Company realized $1.4 million and $2.2 million of income tax benefit for the nine months ended September 30, 2013 and 2012, respectively, which increased its Additional Paid-in-Capital (APIC) pool by $1.4 million as of September 30, 2013. As of September 30, 2013, $4.4 million of unrecognized compensation cost related to stock options granted under the LTSIP is expected to be recognized over a weighted-average period of 2.1 years. During the nine months ended September 30, 2013, QEP received $0.5 million in cash in relation to the exercise of stock options.
	Restricted Shares
	Restricted share grants typically vest in equal installments over a three-year period from the grant date. The grant date fair value is determined based on the closing bid price of the Company's common stock on the grant date. The total fair value of restricted stock that vested during the nine months ended September 30, 2013 and 2012, was $18.4 million and $16.6 million, respectively. The Company realized $0.4 million and $0.2 million of income tax expense for the nine months ended September 30, 2013 and 2012, respectively, with $0.1 million impact to the Company's APIC pool as of September 30, 2013. The weighted average grant-date fair value of restricted stock was $30.03 per share and $30.59 per share for the nine months ended September 30, 2013 and 2012, respectively. As of September 30, 2013, $23.5 million of unrecognized compensation cost related to restricted shares granted under the LTSIP is expected to be recognized over a weighted-average vesting period of 2.2 years.
	Transactions involving restricted shares under the terms of the LTSIP are summarized below:
		Restricted Shares			Weighted-
		Outstanding			Average Grant-Date Fair Value
					(per share)
	Unvested balance at December 31, 2012	1,300,588			$	31.78
	Granted	850,824			30.03
	Vested	(620,065	)		31.42
	Forfeited	(75,442	)		30.82
	Unvested balance at September 30, 2013	1,455,905			$	30.96
	Performance Share Units
	The performance share units' cash payouts are dependent upon the Company’s total shareholder return compared to a group of its peers over a three-year period. The awards are denominated in share units but delivered in cash at the end of the performance period. The weighted average grant-date fair value of the performance share units was $30.12 per share and $30.90 per share for the nine months ended September 30, 2013 and 2012, respectively. As of September 30, 2013, $8.5 million of unrecognized compensation cost, representing the fair market value of performance shares granted under the CIP, is expected to be recognized over a weighted-average vesting period of 2.0 years.
	Transactions involving performance share units under the terms of the CIP are summarized below:
		Performance Share			Weighted-
		Units Outstanding			Average Grant-Date Fair Value
	Unvested balance at December 31, 2012	283,484			$	34.01
	Granted	223,844			30.12
	Vested	—			—
	Forfeited	(1,163	)		30.12
	Unvested balance at September 30, 2013	506,165			$	32.3

Employee_Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefits	'
	Employee Benefits
	The Company maintains closed, defined-benefit pension and postretirement medical plans. QEP's pension plans include a qualified and a nonqualified retirement plan. The Company's postretirement medical plan is unfunded and provides certain health care and life insurance benefits for certain retired employees. During the nine months ended September 30, 2013, the Company made contributions of $8.1 million to its funded pension plan, and $2.7 million to its unfunded pension plan. Contributions to funded plans increase plan assets while contributions to unfunded plans are used to fund current benefit payments. During the remainder of 2013, the Company expects to contribute approximately $0.4 million to its unfunded pension plans and approximately $0.1 million for retiree health care and life insurance benefits. No additional contributions are planned for the funded pension plan during the remainder of 2013.
	The following table sets forth the Company’s pension and postretirement benefits net periodic benefit costs:
		Pension
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(in millions)
	Service cost	$	0.7		$	1.1		$	2.6		$	3
	Interest cost	1.2			1.3			3.7			3.7
	Expected return on plan assets	(0.9		)	(0.9		)	(2.9		)	(2.7		)
	Amortization of prior service costs	1.2			1.3			3.7			3.9
	Amortization of actuarial loss	0.5			0.6			1.7			1
	Periodic expense	$	2.7		$	3.4		$	8.8		$	8.9
		Postretirement Benefits
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(in millions)
	Service cost	$	0.1		$	0.1		$	0.1		$	0.1
	Interest cost	—			—			0.2			0.2
	Amortization of prior service costs	0.1			0.1			0.3			0.3
	Recognized net actuarial loss	0.1			—			0.1			—
	Periodic expense	$	0.3		$	0.2		$	0.7		$	0.6

Operations_by_Line_of_Business

Operations by Line of Business	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Operations by Line of Business	'
	Operations by Line of Business
	QEP’s lines of business include natural gas and oil exploration and production (QEP Energy), midstream field services, which includes the ownership and operation of QEP Midstream (QEP Field Services), and marketing and corporate (QEP Marketing & Resources). The lines of business are managed separately and therefore the financial information is presented separately due to the distinct differences in the nature of operations of each line of business, among other factors. QEP owns a 57.8% ownership interest in QEP Midstream and it is consolidated under the voting interest model in QEP Field Services' operating results. The outside ownership interest in QEP Midstream is presented separately as a noncontrolling interest.
	The following table is a summary of operating results for the three months ended September 30, 2013, by line of business:
		QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
					Services			& Resources						Consolidated
		(in millions)
	Revenues
	From unaffiliated customers	$	538.5		$	66.9		$	167.4		$	—		$	772.8
	From affiliated customers	—			33.2			272.8			(306.0		)	—
	Total Revenues	538.5			100.1			440.2			(306.0		)	772.8
	Operating expenses
	Purchased gas, oil and NGL expense	39.2			—			438.2			(272.4		)	205
	Lease operating expense	43.5			—			—			1.5			45
	Natural gas, oil and NGL transportation and other handling costs	65.1			3.4			—			(34.0		)	34.5
	Gathering, processing and other	—			22			0.4			—			22.4
	General and administrative	33.5			15.8			1.1			(1.1		)	49.3
	Production and property taxes	40.4			2			0.1			—			42.5
	Depreciation, depletion and amortization	236			16.8			0.3			—			253.1
	Other operating expenses	5.6			—			—			—			5.6
	Total operating expenses	463.3			60			440.1			(306.0		)	657.4
	Net gain from asset sales	12.8			—			—			—			12.8
	Operating income (loss)	88			40.1			0.1			—			128.2
	Realized and unrealized losses on derivative contracts	(25.6		)	—			(2.2		)	—			(27.8		)
	Interest and other income	2.6			0.8			52.3			(51.7		)	4
	Income from unconsolidated affiliates	—			0.8			—			—			0.8
	Interest expense	(49.2		)	(3.2		)	(41.0		)	51.7			(41.7		)
	Income before income taxes	15.8			38.5			9.2			—			63.5
	Income tax provision	(6.2		)	(12.7		)	(3.5		)	—			(22.4		)
	Net income	9.6			25.8			5.7			—			41.1
	Net income attributable to noncontrolling interest	—			(3.8		)	—			—			(3.8		)
	Net income attributable to QEP	$	9.6		$	22		$	5.7		$	—		$	37.3
	The following table is a summary of operating results for the three months ended September 30, 2012, by line of business:
		QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
					Services			& Resources						Consolidated
		(in millions)
	Revenues
	From unaffiliated customers	$	374		$	77.9		$	90.5		$	—		$	542.4
	From affiliated customers	—			31.8			145.8			(177.6		)	—
	Total Revenues	374			109.7			236.3			(177.6		)	542.4
	Operating expenses
	Purchased gas, oil and NGL expense	45.9			4.9			236.7			(144.9		)	142.6
	Lease operating expense	43.1			—			—			(0.9		)	42.2
	Natural gas, oil and NGL transportation and other handling costs	59.8			6.9			—			(30.4		)	36.3
	Gathering, processing and other	—			21.8			0.1			0.2			22.1
	General and administrative	31.6			10.5			1.2			(1.6		)	41.7
	Production and property taxes	22.5			1.7			0.1			—			24.3
	Depreciation, depletion and amortization	218.5			15.9			0.2			—			234.6
	Other operating expenses	11.2			—			—			—			11.2
	Total operating expenses	432.6			61.7			238.3			(177.6		)	555
	Operating (loss) income	(58.6		)	48			(2.0		)	—			(12.6		)
	Realized and unrealized gains (losses) on derivative contracts	41.4			(0.6		)	(4.7		)	—			36.1
	Interest and other income	(0.2		)	—			28.4			(28.4		)	(0.2		)
	Income from unconsolidated affiliates	—			2.3			—			—			2.3
	Loss on early extinguishment of debt	—			—			—			—			—
	Interest expense	(24.1		)	(3.5		)	(30.8		)	28.4			(30.0		)
	(Loss) income before income taxes	(41.5		)	46.2			(9.1		)	—			(4.4		)
	Income tax benefit (provision)	15.3			(16.5		)	3.5			—			2.3
	Net (loss) income	(26.2		)	29.7			(5.6		)	—			(2.1		)
	Net income attributable to noncontrolling interest	—			(1.0		)	—			—			(1.0		)
	Net (loss) income attributable to QEP	$	(26.2	)	$	28.7		$	(5.6	)	$	—		$	(3.1	)
	The following table is a summary of operating results for the nine months ended September 30, 2013, by line of business:
		QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
					Services			& Resources						Consolidated
	(in millions)
Revenues
From unaffiliated customers	$	1,575.20		$	203.6		$	441.5		$	—		$	2,220.30
From affiliated customers	—			91.4			711.7			(803.1		)	—
Total Revenues	1,575.20			295			1,153.20			(803.1		)	2,220.30
Operating expenses
Purchased gas, oil and NGL expense	159.8			8.6			1,150.60			(710.2		)	608.8
Lease operating expense	130.2			—			—			(2.8		)	127.4
Natural gas, oil and NGL transportation and other handling costs	180.8			11.6			—			(86.6		)	105.8
Gathering, processing and other	—			65.3			1.2			—			66.5
General and administrative	100.2			36.2			3.3			(3.5		)	136.2
Production and property taxes	112.7			4.8			0.2			—			117.7
Depreciation, depletion and amortization	712.1			44.3			0.7			—			757.1
Other operating expenses	13.5			—			—			—			13.5
Total operating expenses	1,409.30			170.8			1,156.00			(803.1		)	1,933.00
Net gain (loss) from asset sales	113.4			(0.4		)	—			—			113
Operating income (loss)	279.3			123.8			(2.8		)	—			400.3
Realized and unrealized gains on derivative contracts	49.6			—			2			—			51.6
Interest and other income	7.5			1.1			158.2			(157.7		)	9.1
Income from unconsolidated affiliates	—			3.7			—			—			3.7
Interest expense	(143.4		)	(12.5		)	(124.3		)	157.7			(122.5		)
Income before income taxes	193			116.1			33.1			—			342.2
Income tax provision	(71.1		)	(40.3		)	(13.6		)	—			(125.0		)
Net income	121.9			75.8			19.5			—			217.2
Net income attributable to noncontrolling interest	—			(5.8		)	—			—			(5.8		)
Net income attributable to QEP	$	121.9		$	70		$	19.5		$	—		$	211.4
The following table is a summary of operating results for the nine months ended September 30, 2012, by line of business:
	QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
				Services			& Resources						Consolidated
	(in millions)
Revenues
From unaffiliated customers	$	1,106.30		$	254.9		$	283.7		$	—		$	1,644.90
From affiliated customers	—			88.1			396.3			(484.4		)	—
Total Revenues	1,106.30			343			680			(484.4		)	1,644.90
Operating expenses
Purchased gas, oil and NGL expense	159			9			681.7			(393.8		)	455.9
Lease operating expense	125.3			—			—			(2.5		)	122.8
Natural gas, oil and NGL transportation and other handling costs	167.4			27.7			—			(83.6		)	111.5
Gathering, processing and other	—			65.6			0.8			—			66.4
General and administrative	92.7			23.7			2.6			(4.5		)	114.5
Production and property taxes	63.6			4.6			0.2			—			68.4
Depreciation, depletion and amortization	600.2			47.6			0.5			—			648.3
Other operating expenses	77.2			—			—			—			77.2
Total operating expenses	1,285.40			178.2			685.8			(484.4		)	1,665.00
Net gain from asset sales	1.5			—			—			—			1.5
Operating (loss) income	(177.6		)	164.8			(5.8		)	—			(18.6		)
Realized and unrealized gains (losses) on derivative contracts	330.4			8.3			(4.0		)	—			334.7
Interest and other income	2.2			0.1			81.1			(81.0		)	2.4
Income from unconsolidated affiliates	0.1			5.5			—			—			5.6
Loss on early extinguishment of debt	—			—			(0.6		)	—			(0.6		)
Interest expense	(71.1		)	(9.4		)	(83.4		)	81			(82.9		)
Income (loss) before income taxes	84			169.3			(12.7		)	—			240.6
Income taxes	(32.4		)	(59.2		)	5.1			—			(86.5		)
Net income (loss)	51.6			110.1			(7.6		)	—			154.1
Net income attributable to noncontrolling interest	—			(2.7		)	—			—			(2.7		)
Net income (loss) attributable to QEP	$	51.6		$	107.4		$	(7.6	)	$	—		$	151.4

Basis_of_Presentation_of_Inter1

Basis of Presentation of Interim Consolidated Financial Statements (Policies)	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
New accounting pronouncements	'
	New accounting pronouncements
	In February of 2013, the FASB issued ASU 2013-02, Other Comprehensive Income (Topic 220: Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income), which seeks to improve the reporting of entities by requiring an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required under GAAP to be reclassified in its entirety to net income. For other amounts that are not required under GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under GAAP that provide additional detail about those amounts. The amendments are effective prospectively for reporting periods beginning on or after December 15, 2012. The Company adopted this standard in the first quarter of 2013 and noted that it did not have a significant impact on the Company's consolidated financial statements.
	In December of 2011, the FASB issued ASU 2011-11, Disclosures about Offsetting Assets and Liabilities, which enhances disclosure requirements regarding an entity’s financial instruments and derivative instruments that are offset or subject to a master netting arrangement. This information about offsetting and related netting arrangements will enable users of financial statements to understand the effect of those arrangements on the entity’s financial position, including the effect of rights of setoff. Additionally, the FASB issued ASU 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities, which clarifies the implementation of ASU 2011-01. The amendments are required for annual reporting periods beginning after January 1, 2013, and interim periods within those annual periods. The Company adopted this standard effective January 1, 2013. It did not have a significant impact on the Company's consolidated financial statements.
	In July of 2012, the FASB issued ASU 2012-02, Intangibles - Goodwill and Other: Testing Indefinite-Lived Intangible Assets for Impairment, which revises the way an entity can test indefinite-lived intangible assets for impairment by allowing an entity to first assess qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that the indefinite-lived intangible asset is impaired. If there is no indication of impairment from the qualitative impairment test, the entity is not required to complete a quantitative impairment test of determining and comparing the fair value with the carrying amount of the indefinite-lived asset. Under the guidance in this ASU, an entity also has the option to bypass the qualitative assessment in any period and proceed directly to performing the quantitative impairment test, while retaining the ability to resume performing the qualitative assessment in any subsequent period. The amendments are effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. The Company adopted this standard January 1, 2013, which has allowed the Company to more efficiently complete the annual goodwill impairment test but has not had a significant impact on the Company's consolidated financial statements.

QEP_Midstream_Tables

QEP Midstream (Tables)	9 Months Ended
	Sep. 30, 2013
QEP Midstream [Abstract]	'
Schedule of Sale of Stock by Subsidiary or Equity Method Investee Disclosure [Table Text Block]	'
	The following table is a reconciliation of proceeds from the initial public offering (in millions):
	Total proceeds from the Offering	$	483
	Offering costs	(33.4		)
	Net proceeds from the Offering	449.6
	Revolving credit facility origination fees	(3.0		)
	Repayment of outstanding debt with QEP	(95.5		)
	Net proceeds distributed to QEP from the Offering	$	351.1

Acquisitions_Divestitures_Tabl

Acquisitions & Divestitures (Tables)	9 Months Ended
	Sep. 30, 2013
Acquisitions [Abstract]	'
Schedule of Purchase Price Allocation [Table Text Block]	'
	The following table presents a summary of the Company's purchase accounting entries:
		As of September, 2013
		(in millions)
	Consideration given:
	Cash consideration	$	1,392.70
	Amounts recognized for fair value of assets acquired and liabilities assumed:
	Proved properties	$	713.8
	Unproved properties	683.4
	Asset retirement obligations	(0.9		)
	Liabilities assumed	(4.4		)
	Other assets	0.8
	Total fair value	$	1,392.70
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]	'
Business Acquisition, Pro Forma Information [Table Text Block]	'
	The following unaudited, pro forma results of operations are provided for the three and nine months ended September 30, 2012. These supplemental pro forma results of operations are provided for illustrative purposes only and may not be indicative of the actual results that would have been achieved by the acquired properties for the period presented or that may be achieved by such properties in the future. Future results may vary significantly from the results reflected in this pro forma financial information because of future events and transactions, as well as other factors. The pro forma information is based on QEP's consolidated results of operations for the three and nine months ended September 30, 2012, on the acquired properties' historical results of operations and on estimates of the effect of the transaction on the combined results. The pro forma results of operations have been prepared by adjusting the historical results of QEP to include the historical results of the acquired properties based on information provided by the seller and the impact of the purchase price allocation. The pro forma results of operations do not include any cost savings or other synergies that may result from the 2012 Acquisition or any estimated costs that have been or will be incurred by the Company to integrate the acquired properties.
		Three Months Ended					Nine Months Ended
		30-Sep-12					30-Sep-12
		Actual			Pro forma		Actual		Pro forma
		(in millions, except per share data)
	Revenues	$	542.4		$	598.9	$	1,644.90	$	1,780.40
	Net income attributable to QEP	(3.1		)	4.8		151.4		164.9
	Earnings per common share attributable to QEP
	Basic	$	(0.02	)	$	0.03	$	0.85	$	0.93
	Diluted	(0.02		)	0.03		0.85		0.93

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Components of basic and diluted shares used in EPS	'
	A reconciliation of the components of basic and diluted shares used in the EPS calculation follows:
		Three Months Ended		Nine Months Ended
		September 30,		September 30,
		2013	2012	2013	2012
		(in millions)
	Weighted-average basic common shares outstanding	179.3	177.9	179.2	177.6
	Potential number of shares issuable upon exercise of in-the-money stock options under the Long-term Stock Incentive Plan	0.2	—	0.2	1
	Average diluted common shares outstanding	179.5	177.9	179.4	178.6

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]	'
Asset retirement obligations roll forward	'
	The following is a reconciliation of the changes in the Company's asset retirement obligation from January 1, 2013, to September 30, 2013:
		Asset Retirement Obligations
		2013
		(in millions)
	ARO liability at January 1,	$	193.1
	Accretion	7.2
	Liabilities incurred	8.7
	Revisions	(25.3		)
	Liabilities settled	(13.5		)
	ARO liability at September 30,	$	170.2

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair value of financial assets and liabilities	'
	The fair value of financial assets and liabilities at September 30, 2013, is shown in the table below:
		Fair Value Measurements
		30-Sep-13
		Gross Amounts of Assets and Liabilities						Netting			Net Amounts Presented on the Condensed Consolidated Balance Sheet
		Level 1		Level 2		Level 3		Adjustments(1)
		(in millions)
	Financial Assets
	Commodity derivative instruments - short-term	$	—	$	58	$	—	$	(18.6	)	$	39.4
	Commodity derivative instruments - long-term	—		5.8		—		—			5.8
	Total financial assets	$	—	$	63.8	$	—	$	(18.6	)	$	45.2
	Financial Liabilities
	Commodity derivative instruments - short-term	$	—	$	26.2	$	—	$	(18.6	)	$	7.6
	Interest rate swaps - short-term	—		2.5		—		—			2.5
	Total financial liabilities	$	—	$	28.7	$	—	$	(18.6	)	$	10.1
	The fair value of financial assets and liabilities at December 31, 2012, is shown in the table below:
		Fair Value Measurements
		31-Dec-12
		Gross Amounts of Assets and Liabilities						Netting			Net Amounts Presented on the Condensed Consolidated Balance Sheet
		Level 1		Level 2		Level 3		Adjustments(1)
		(in millions)
	Financial Assets
	Commodity derivative instruments - short-term	$	—	$	189.7	$	—	$	(1.0	)	$	188.7
	Commodity derivative instruments - long-term	—		4.2		—		(0.1		)	4.1
	Total financial assets	$	—	$	193.9	$	—	$	(1.1	)	$	192.8
	Financial Liabilities
	Commodity derivative instruments - short-term	$	—	$	1	$	—	$	(1.0	)	$	—
	Interest rate swaps - short-term	—		2.6		—		—			2.6
	Commodity derivative instruments - long-term	—		0.1		—		(0.1		)	—
	Interest rate swaps - long-term	—		3.6		—		—			3.6
	Total financial liabilities	$	—	$	7.3	$	—	$	(1.1	)	$	6.2
Fair value and related carrying amount of certain financial instruments	'
	The following table discloses the fair value and related carrying amount of certain financial instruments not disclosed in other notes to the condensed consolidated financial statements in this quarterly report on Form 10-Q:
		Carrying		Level 1		Carrying		Level 1
		Amount		Fair Value		Amount		Fair Value
		September 30, 2013				December 31, 2012
		(in millions)
	Financial assets
	Cash and cash equivalents	$	123	$	123	$	—	$	—
	Financial liabilities
	Checks outstanding in excess of cash balances	$	1.6	$	1.6	$	39.7	$	39.7
	Long-term debt	$	2,882.30	$	2,900.50	$	3,206.90	$	3,420.70

Derivative_Contracts_Tables

Derivative Contracts (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Volumes and Average Prices	'
	QEP Energy Derivative Contracts
	The following table sets forth QEP Energy’s quantities and average prices for its commodity derivative contracts as of September 30, 2013:
	Insert Title Here
	Year		Type of Contract		Index	Total			Average Swap price per unit
						Volumes
						(in millions)
	Natural gas					(MMBtu)
	2013		Swap		IFNPCR(1)	18.4			$	5.49
	2013		Swap		NYMEX	14.7			$	3.81
	2014		Swap		IFNPCR(1)	32.9			$	4
	2014		Swap		NYMEX	25.6			$	4.19
	Crude oil					(Bbls)
	2013		Swap		NYMEX WTI	2.1			$	98.27
	2013		Swap		BRENT ICE	0.1			$	107.8
	2014		Swap		NYMEX WTI	8.8			$	93.63
	(1)	Inside FERC monthly settlement index for the Northwest Pipeline Corp. Rocky Mountains.
	QEP Marketing Derivative Contracts
	QEP Marketing enters into commodity derivative transactions to lock in a margin on natural gas volumes placed into storage and for marketing transactions in which QEP Marketing sells gas volumes at a fixed price. The following table sets forth QEP Marketing’s volumes and swap prices for its commodity derivative contracts as of September 30, 2013:
	Year		Type of Contract		Index	Total			Average Swap price
						Volumes			per MMBtu
						(in millions)
	Natural gas sales					(MMBtu)
	2013		Swap		IFNPCR	1.6			$	3.91
	2014		Swap		IFNPCR	3.8			$	3.71
	Natural gas purchases					(MMBtu)
	2013		Swap		IFNPCR	1.7			$	3.46
	2014		Swap		IFNPCR	0.2			$	3.82
	QEP's Derivative Contracts
	The following table sets forth QEP’s notional amount and interest rate for its interest rate swaps outstanding as of September 30, 2013:
	Notional amount		Type of Contract		Maturity	Fixed Rate Paid		Variable Rate Received
	(in millions)
	$300.00		Swap		Mar-17	1.07%		One month LIBOR
Fair values of Derivatives by Balance Sheet Location	'
	The following table identifies the balance sheet location of QEP’s outstanding derivative contracts on a gross contract basis as opposed to the net contract basis presentation in the Condensed Consolidated Balance Sheets and the related fair values at the balance sheet dates:
				Gross asset derivative							Gross liability derivative
				instruments fair value							instruments fair value
		Balance Sheet		September 30,			31-Dec-12				September 30,			31-Dec-12
		line item		2013							2013
				(in millions)							(in millions)
	Current:
	Commodity	Fair value of derivative contracts		$	58		$	189.7			$	26.2		$	1
	Interest rate swaps	Fair value of derivative contracts		—			—				2.5			2.6
	Long-term:
	Commodity	Fair value of derivative contracts		5.8			4.2				—			0.1
	Interest rate swaps	Fair value of derivative contracts		—			—				—			3.6
	Total derivative instruments			$	63.8		$	193.9			$	28.7		$	7.3
Effects of Derivative Transactions	'
	The effects of the change in fair value and settlement of QEP's derivative contracts recorded in "Realized and unrealized (losses) gains on derivative contracts" on the Condensed Consolidated Statements of Operations are summarized in the following tables:
			Three Months Ended							Nine Months Ended
	Derivative instruments not designated as cash flow hedges		September 30,							September 30,
			2013			2012				2013			2012
	Realized gains (losses) on commodity derivative contracts		(in millions)
	QEP Energy
	Natural gas derivative contracts		$	42.5		$	86.2			$	112		$	283.8
	Oil derivative contracts		(15.3		)	2.7				(3.7		)	2.2
	NGL derivative contracts		—			3.4				—			6.5
	QEP Field Services
	NGL derivative contracts		—			1.9				—			6.3
	QEP Marketing
	Natural gas derivative contracts		(0.3		)	(0.4		)		0.7			3.7
	Total realized gains on commodity derivative contracts		26.9			93.8				109			302.5
	Unrealized gains (losses) on commodity derivative contracts
	QEP Energy
	Natural gas derivative contracts		(6.6		)	(50.6		)		(9.6		)	3.3
	Oil derivative contracts		(46.2		)	4.1				(49.1		)	31.2
	NGL derivative contracts		—			(4.4		)		—			3.4
	QEP Field Services
	NGL derivative contracts		—			(2.5		)		—			2
	QEP Marketing
	Natural gas derivative contracts		0.1			(1.4		)		(0.3		)	(0.5		)
	Total unrealized (losses) gains on commodity derivative contracts		(52.7		)	(54.8		)		(59.0		)	39.4
	Total realized and unrealized (losses) gains on commodity derivative contracts		$	(25.8	)	$	39			$	50		$	341.9
	Realized gains (losses) on interest rate swaps
	Realized losses on interest rate swaps		$	(0.6	)	$	(0.6	)		$	(1.9	)	$	(0.6	)
	Unrealized gains (losses) on interest rate swaps
	Unrealized (losses) gains on interest rate swaps		(1.4		)	(2.3		)		3.5			(6.6		)
	Total realized and unrealized (losses) gains on interest rate swaps		$	(2.0	)	$	(2.9	)		$	1.6		$	(7.2	)
	Total net realized gains on derivative contracts		$	26.3		$	93.2			$	107.1		$	301.9
	Total net unrealized (losses) gains on derivative contracts		(54.1		)	(57.1		)		(55.5		)	32.8
	Grand Total		$	(27.8	)	$	36.1			$	51.6		$	334.7

Restructuring_Costs_Tables

Restructuring Costs (Tables)	9 Months Ended
	Sep. 30, 2013
Restructuring Costs [Abstract]	'
Reconciliation of QEP Energy's restructuring cost	'
	The following table summarizes, by line of business, each major type of cost expected to be incurred and the total amounts recorded in "General and administrative" expense on the Condensed Consolidated Statement of Operations for the respective periods indicated:
		Total Restructuring Costs
		Total Expected to be Incurred			Recognized in Income
					Period from Inception to September 30, 2013			Three Months Ended September 30, 2013						Nine Months Ended September 30, 2013
								2013			2012			2013		2012
	QEP Energy	(in millions)
	One-time termination benefits	$	3.3		$	3.3		$	0.1		$	0.2		0.4		2.1
	Retention & relocation expense	3.7			3.6			0.1			0.1			0.3		3.2
	Lease termination costs	0.6			0.6			—			—			—		—
	Total restructuring costs	$	7.6		$	7.5		$	0.2		$	0.3		0.7		5.3
	QEP Field Services
	One-time termination benefits	$	—		$	—		$	—		$	—		—		—
	Retention & relocation expense	0.1			0.1			0.1			—			0.1		—
	Lease termination costs	—			—			—			—			—		—
	Total restructuring costs	$	0.1		$	0.1		$	0.1		$	—		0.1		—
	QEP Marketing
	One-time termination benefits	$	0.3		$	0.3		$	—		$	—		0.1		—
	Retention & relocation expense	—			—			—			—			—		—
	Lease termination costs	—			—			—			—			—		—
	Total restructuring costs	$	0.3		$	0.3		$	—		$	—		0.1		—
	Total QEP
	One-time termination benefits	$	3.6		$	3.6		$	0.1		$	0.2		$	0.5	$	2.1
	Retention & relocation expense	3.8			3.7			0.2			0.1			0.4		3.2
	Lease termination costs	0.6			0.6			—			—			—		—
	Total restructuring costs	$	8		$	7.9		$	0.3		$	0.3		$	0.9	$	5.3
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]	'
		QEP Energy			QEP Field Services			QEP Marketing			Total
		(in millions)
	Balance at December 31, 2012	$	1		$	—		$	—		$	1
	Costs incurred and charged to expense	0.7			0.1			0.1			0.9
	Costs paid or otherwise settled	(1.7		)	(0.1		)	(0.1		)	(1.9		)
	Balance at September 30, 2013	$	—		—			—			$	—

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Debt Outstanding	'
	As of the indicated dates, the principal amount of QEP’s debt, including amounts outstanding under its and QEP Midstream's revolving credit facilities, QEP's term loan and QEP's senior notes consisted of the following:
		September 30,			December 31,
		2013			2012
		(in millions)
	QEP's revolving credit facility due 2016	$	365		$	690
	QEP Midstream's revolving credit facility due 2018	—			—
	Term loan due 2017	300			300
	6.05% Senior Notes due 2016	176.8			176.8
	6.80% Senior Notes due 2018	134			134
	6.80% Senior Notes due 2020	136			136
	6.875% Senior Notes due 2021	625			625
	5.375% Senior Notes due 2022	500			500
	5.25% Senior Notes due 2023	650			650
	Total principal amount of debt	2,886.80			3,211.80
	Less unamortized discount	(4.5		)	(4.9		)
	Total long-term debt outstanding	$	2,882.30		$	3,206.90

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Schedule of calculated fair value of options granted and major assumptions used	'
	The calculated fair value of options granted and major assumptions used in the model at the date of grant are listed below:
		Stock Option Assumptions
		Nine Months Ended
		30-Sep-13
	Weighted-average grant-date fair value of awards granted during the period	$	15.16
	Weighted-average risk-free interest rate	1		%
	Weighted-average expected price volatility	58.3		%
	Expected dividend yield	0.27		%
	Expected term in years at the date of grant	5.5
Summary of stock option transactions under the terms of LTSIP	'
	Stock option transactions under the terms of the LTSIP are summarized below:
		Options			Weighted-		Weighted-Average	Aggregate
		Outstanding			Average Exercise Price		Remaining	Intrinsic Value
							Contractual Term
					(per share)		(in years)	(in millions)
	Outstanding at December 31, 2012	1,697,471			$	25.23
	Granted	330,592			30.06
	Exercised	(209,500	)		9.6
	Forfeited	—			—
	Outstanding at September 30, 2013	1,818,563			$	27.9	3.9	$	3.6
	Options Exercisable at September 30, 2013	1,236,211			$	26.36	3	$	3.6
	Unvested Options at September 30, 2013	582,352			$	31.18	5.9	$	—
Restricted Shares and Performance Share Units Activity	'
	Restricted Shares
	Restricted share grants typically vest in equal installments over a three-year period from the grant date. The grant date fair value is determined based on the closing bid price of the Company's common stock on the grant date. The total fair value of restricted stock that vested during the nine months ended September 30, 2013 and 2012, was $18.4 million and $16.6 million, respectively. The Company realized $0.4 million and $0.2 million of income tax expense for the nine months ended September 30, 2013 and 2012, respectively, with $0.1 million impact to the Company's APIC pool as of September 30, 2013. The weighted average grant-date fair value of restricted stock was $30.03 per share and $30.59 per share for the nine months ended September 30, 2013 and 2012, respectively. As of September 30, 2013, $23.5 million of unrecognized compensation cost related to restricted shares granted under the LTSIP is expected to be recognized over a weighted-average vesting period of 2.2 years.
	Transactions involving restricted shares under the terms of the LTSIP are summarized below:
		Restricted Shares			Weighted-
		Outstanding			Average Grant-Date Fair Value
					(per share)
	Unvested balance at December 31, 2012	1,300,588			$	31.78
	Granted	850,824			30.03
	Vested	(620,065	)		31.42
	Forfeited	(75,442	)		30.82
	Unvested balance at September 30, 2013	1,455,905			$	30.96
	Performance Share Units
	The performance share units' cash payouts are dependent upon the Company’s total shareholder return compared to a group of its peers over a three-year period. The awards are denominated in share units but delivered in cash at the end of the performance period. The weighted average grant-date fair value of the performance share units was $30.12 per share and $30.90 per share for the nine months ended September 30, 2013 and 2012, respectively. As of September 30, 2013, $8.5 million of unrecognized compensation cost, representing the fair market value of performance shares granted under the CIP, is expected to be recognized over a weighted-average vesting period of 2.0 years.
	Transactions involving performance share units under the terms of the CIP are summarized below:
		Performance Share			Weighted-
		Units Outstanding			Average Grant-Date Fair Value
	Unvested balance at December 31, 2012	283,484			$	34.01
	Granted	223,844			30.12
	Vested	—			—
	Forfeited	(1,163	)		30.12
	Unvested balance at September 30, 2013	506,165			$	32.3

Employee_Benefits_Tables

Employee Benefits (Tables)	9 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]	'
Pension and Other Postretirement Benefit Costs	'
		Pension
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(in millions)
	Service cost	$	0.7		$	1.1		$	2.6		$	3
	Interest cost	1.2			1.3			3.7			3.7
	Expected return on plan assets	(0.9		)	(0.9		)	(2.9		)	(2.7		)
	Amortization of prior service costs	1.2			1.3			3.7			3.9
	Amortization of actuarial loss	0.5			0.6			1.7			1
	Periodic expense	$	2.7		$	3.4		$	8.8		$	8.9
		Postretirement Benefits
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(in millions)
	Service cost	$	0.1		$	0.1		$	0.1		$	0.1
	Interest cost	—			—			0.2			0.2
	Amortization of prior service costs	0.1			0.1			0.3			0.3
	Recognized net actuarial loss	0.1			—			0.1			—
	Periodic expense	$	0.3		$	0.2		$	0.7		$	0.6

Operations_by_Line_of_Business1

Operations by Line of Business (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Summary of operating results by line of business	'
	Operations by Line of Business
	QEP’s lines of business include natural gas and oil exploration and production (QEP Energy), midstream field services, which includes the ownership and operation of QEP Midstream (QEP Field Services), and marketing and corporate (QEP Marketing & Resources). The lines of business are managed separately and therefore the financial information is presented separately due to the distinct differences in the nature of operations of each line of business, among other factors. QEP owns a 57.8% ownership interest in QEP Midstream and it is consolidated under the voting interest model in QEP Field Services' operating results. The outside ownership interest in QEP Midstream is presented separately as a noncontrolling interest.
	The following table is a summary of operating results for the three months ended September 30, 2013, by line of business:
		QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
					Services			& Resources						Consolidated
		(in millions)
	Revenues
	From unaffiliated customers	$	538.5		$	66.9		$	167.4		$	—		$	772.8
	From affiliated customers	—			33.2			272.8			(306.0		)	—
	Total Revenues	538.5			100.1			440.2			(306.0		)	772.8
	Operating expenses
	Purchased gas, oil and NGL expense	39.2			—			438.2			(272.4		)	205
	Lease operating expense	43.5			—			—			1.5			45
	Natural gas, oil and NGL transportation and other handling costs	65.1			3.4			—			(34.0		)	34.5
	Gathering, processing and other	—			22			0.4			—			22.4
	General and administrative	33.5			15.8			1.1			(1.1		)	49.3
	Production and property taxes	40.4			2			0.1			—			42.5
	Depreciation, depletion and amortization	236			16.8			0.3			—			253.1
	Other operating expenses	5.6			—			—			—			5.6
	Total operating expenses	463.3			60			440.1			(306.0		)	657.4
	Net gain from asset sales	12.8			—			—			—			12.8
	Operating income (loss)	88			40.1			0.1			—			128.2
	Realized and unrealized losses on derivative contracts	(25.6		)	—			(2.2		)	—			(27.8		)
	Interest and other income	2.6			0.8			52.3			(51.7		)	4
	Income from unconsolidated affiliates	—			0.8			—			—			0.8
	Interest expense	(49.2		)	(3.2		)	(41.0		)	51.7			(41.7		)
	Income before income taxes	15.8			38.5			9.2			—			63.5
	Income tax provision	(6.2		)	(12.7		)	(3.5		)	—			(22.4		)
	Net income	9.6			25.8			5.7			—			41.1
	Net income attributable to noncontrolling interest	—			(3.8		)	—			—			(3.8		)
	Net income attributable to QEP	$	9.6		$	22		$	5.7		$	—		$	37.3
	The following table is a summary of operating results for the three months ended September 30, 2012, by line of business:
		QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
					Services			& Resources						Consolidated
		(in millions)
	Revenues
	From unaffiliated customers	$	374		$	77.9		$	90.5		$	—		$	542.4
	From affiliated customers	—			31.8			145.8			(177.6		)	—
	Total Revenues	374			109.7			236.3			(177.6		)	542.4
	Operating expenses
	Purchased gas, oil and NGL expense	45.9			4.9			236.7			(144.9		)	142.6
	Lease operating expense	43.1			—			—			(0.9		)	42.2
	Natural gas, oil and NGL transportation and other handling costs	59.8			6.9			—			(30.4		)	36.3
	Gathering, processing and other	—			21.8			0.1			0.2			22.1
	General and administrative	31.6			10.5			1.2			(1.6		)	41.7
	Production and property taxes	22.5			1.7			0.1			—			24.3
	Depreciation, depletion and amortization	218.5			15.9			0.2			—			234.6
	Other operating expenses	11.2			—			—			—			11.2
	Total operating expenses	432.6			61.7			238.3			(177.6		)	555
	Operating (loss) income	(58.6		)	48			(2.0		)	—			(12.6		)
	Realized and unrealized gains (losses) on derivative contracts	41.4			(0.6		)	(4.7		)	—			36.1
	Interest and other income	(0.2		)	—			28.4			(28.4		)	(0.2		)
	Income from unconsolidated affiliates	—			2.3			—			—			2.3
	Loss on early extinguishment of debt	—			—			—			—			—
	Interest expense	(24.1		)	(3.5		)	(30.8		)	28.4			(30.0		)
	(Loss) income before income taxes	(41.5		)	46.2			(9.1		)	—			(4.4		)
	Income tax benefit (provision)	15.3			(16.5		)	3.5			—			2.3
	Net (loss) income	(26.2		)	29.7			(5.6		)	—			(2.1		)
	Net income attributable to noncontrolling interest	—			(1.0		)	—			—			(1.0		)
	Net (loss) income attributable to QEP	$	(26.2	)	$	28.7		$	(5.6	)	$	—		$	(3.1	)
	The following table is a summary of operating results for the nine months ended September 30, 2013, by line of business:
		QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
					Services			& Resources						Consolidated
	(in millions)
Revenues
From unaffiliated customers	$	1,575.20		$	203.6		$	441.5		$	—		$	2,220.30
From affiliated customers	—			91.4			711.7			(803.1		)	—
Total Revenues	1,575.20			295			1,153.20			(803.1		)	2,220.30
Operating expenses
Purchased gas, oil and NGL expense	159.8			8.6			1,150.60			(710.2		)	608.8
Lease operating expense	130.2			—			—			(2.8		)	127.4
Natural gas, oil and NGL transportation and other handling costs	180.8			11.6			—			(86.6		)	105.8
Gathering, processing and other	—			65.3			1.2			—			66.5
General and administrative	100.2			36.2			3.3			(3.5		)	136.2
Production and property taxes	112.7			4.8			0.2			—			117.7
Depreciation, depletion and amortization	712.1			44.3			0.7			—			757.1
Other operating expenses	13.5			—			—			—			13.5
Total operating expenses	1,409.30			170.8			1,156.00			(803.1		)	1,933.00
Net gain (loss) from asset sales	113.4			(0.4		)	—			—			113
Operating income (loss)	279.3			123.8			(2.8		)	—			400.3
Realized and unrealized gains on derivative contracts	49.6			—			2			—			51.6
Interest and other income	7.5			1.1			158.2			(157.7		)	9.1
Income from unconsolidated affiliates	—			3.7			—			—			3.7
Interest expense	(143.4		)	(12.5		)	(124.3		)	157.7			(122.5		)
Income before income taxes	193			116.1			33.1			—			342.2
Income tax provision	(71.1		)	(40.3		)	(13.6		)	—			(125.0		)
Net income	121.9			75.8			19.5			—			217.2
Net income attributable to noncontrolling interest	—			(5.8		)	—			—			(5.8		)
Net income attributable to QEP	$	121.9		$	70		$	19.5		$	—		$	211.4
The following table is a summary of operating results for the nine months ended September 30, 2012, by line of business:
	QEP Energy			QEP Field			QEP Marketing			Eliminations			QEP
				Services			& Resources						Consolidated
	(in millions)
Revenues
From unaffiliated customers	$	1,106.30		$	254.9		$	283.7		$	—		$	1,644.90
From affiliated customers	—			88.1			396.3			(484.4		)	—
Total Revenues	1,106.30			343			680			(484.4		)	1,644.90
Operating expenses
Purchased gas, oil and NGL expense	159			9			681.7			(393.8		)	455.9
Lease operating expense	125.3			—			—			(2.5		)	122.8
Natural gas, oil and NGL transportation and other handling costs	167.4			27.7			—			(83.6		)	111.5
Gathering, processing and other	—			65.6			0.8			—			66.4
General and administrative	92.7			23.7			2.6			(4.5		)	114.5
Production and property taxes	63.6			4.6			0.2			—			68.4
Depreciation, depletion and amortization	600.2			47.6			0.5			—			648.3
Other operating expenses	77.2			—			—			—			77.2
Total operating expenses	1,285.40			178.2			685.8			(484.4		)	1,665.00
Net gain from asset sales	1.5			—			—			—			1.5
Operating (loss) income	(177.6		)	164.8			(5.8		)	—			(18.6		)
Realized and unrealized gains (losses) on derivative contracts	330.4			8.3			(4.0		)	—			334.7
Interest and other income	2.2			0.1			81.1			(81.0		)	2.4
Income from unconsolidated affiliates	0.1			5.5			—			—			5.6
Loss on early extinguishment of debt	—			—			(0.6		)	—			(0.6		)
Interest expense	(71.1		)	(9.4		)	(83.4		)	81			(82.9		)
Income (loss) before income taxes	84			169.3			(12.7		)	—			240.6
Income taxes	(32.4		)	(59.2		)	5.1			—			(86.5		)
Net income (loss)	51.6			110.1			(7.6		)	—			154.1
Net income attributable to noncontrolling interest	—			(2.7		)	—			—			(2.7		)
Net income (loss) attributable to QEP	$	51.6		$	107.4		$	(7.6	)	$	—		$	151.4

QEP_Midstream_Details

QEP Midstream (Details) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Aug. 14, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Noncontrolling Interest [Line Items]	'	'	'	'
Noncontrolling Interest, Ownership Percentage by Parent	0.00%	0.00%	0.00%	'
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	'	'	0.00%	'
Limited Partners' Capital Account, Units Issued	6,701,750	'	'	'
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	0.00%	0.00%	'	'
Other Ownership Interests, Units Issued	26,705,000	'	'	'
General Partners' Capital Account, Units Issued	1,090,000	'	'	'
Total proceeds from the Offering	$420	$483	$449.60	$0
Initial Offering Period	'August 14, 2013	'	'	'
Partners' Capital Account, Units, Sold in Public Offering	20,000,000	'	'	'
Partners Capital Account Units Sold In Public Offering Price Per Unit	$21	'	'	'
net proceeds from issuance of units to underwriters	58.9	'	'	'
Offering Costs from issuance of Units to Underwriters	4.1	'	'	'
Partners' Capital Account, Public Sale of Units Net of Offering Costs	390.7	449.6	'	'
Offering Costs, Partnership Interests	29.3	'	'	'
Offering Costs, Partnership Interests	'	-33.4	'	'
Partners' Capital Account, Units, Sold to Underwriters	3,000,000	'	'	'
Revolving credit facility origination fees	'	-3	3	17
Repayment of outstanding debt with QEP	'	-95.5	'	'
Net proceeds distributed to QEP from the Offering	'	351.1	'	'
Related Party Transaction, Expenses from Transactions with Related Party	13.8	'	'	'
Management Fees, Base Revenue	$1.40	'	'	'

Acquisitions_Divestitures_Deta

Acquisitions & Divestitures (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Business Acquisition [Line Items]	'	'	'	'
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$76	'	$190.10	'
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	19.2	'	42.5	'
Business Combination, Consideration Given [Abstract]	'	'	'	'
Cash consideration	1,392.70	'	1,392.70	'
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]	'	'	'	'
Proved properties	713.8	'	713.8	'
Unproved Properties	683.4	'	683.4	'
Asset retirement obligations	-0.9	'	-0.9	'
Liabilities assumed	-4.4	'	-4.4	'
Other assets	0.8	'	0.8	'
Total fair value	1,392.70	'	1,392.70	'
Business Acquisition, Pro Forma Information [Abstract]	'	'	'	'
Business Acquisition, Pro Forma Revenue	'	598.9	'	1,780.40
Business Acquisition, Pro Forma Net Income (Loss)	'	4.8	'	164.9
Business Acquisition, Pro Forma Earnings Per Share, Basic	'	$0.03	'	$0.93
Business Acquisition, Pro Forma Earnings Per Share, Diluted	'	$0.03	'	$0.93
Busines Acquisition, Actual Information [Abstract]	'	'	'	'
Oil and Gas Revenue	772.8	542.4	2,220.30	1,644.90
Net Income (Loss) Attributable to Parent	$37.30	($3.10)	$211.40	$151.40
Earnings Per Share, Basic	$0.21	($0.02)	$1.18	$0.85
Earnings Per Share, Diluted	$0.21	($0.02)	$1.18	$0.85

Acquisitions_Divestitures_Dive

Acquisitions & Divestitures Divestitures (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Second Quarter Property Divestitures [Member]	'
Significant Acquisitions and Disposals [Line Items]	'
Proceeds from Sale of Property, Plant, and Equipment	$140.20
Gain (Loss) on Sale of Property	97.4
Third Quarter Property Divestitures [Member]	'
Significant Acquisitions and Disposals [Line Items]	'
Proceeds from Sale of Property, Plant, and Equipment	68.8
Gain (Loss) on Sale of Property	$17.50

Earnings_Per_Share_Details

Earnings Per Share (Details)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Anti-dilutive shares not included in diluted common share outstanding (in shares)	'	'	'	0.8
Weighted-average basic common shares outstanding (in shares)	179.3	177.9	179.2	177.6
Potential number of shares issuable upon excerise of in-the-money stock options under the Long-term Stock Incentive Plan	0.2	0	0.2	1
Average diluted common shares outstanding (in shares)	179.5	177.9	179.4	178.6

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
ARO Liability [Roll Forward]	'
ARO liability, Beginning Balance	$193.10
Accretion	7.2
Liabilities incurred	8.7
Revisions	-25.3
Liabilities settled	-13.5
ARO liability, Ending Balance	$170.20

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	$123	$0	$0	$0
Cash and Cash Equivalents, Fair Value Disclosure	123	0	'	'
Financial Assets	'	'	'	'
Derivative Asset, Fair Value, Gross	63.8	193.9	'	'
Financial liabilities	'	'	'	'
Derivative instruments - long-term	0	3.6	'	'
Fair Value, Measurements, Recurring [Member]	'	'	'	'
Financial Assets	'	'	'	'
Total financial assets	45.2	192.8	'	'
Financial liabilities	'	'	'	'
Total financial liabilities	10.1	6.2	'	'
Fair Value, Measurements, Recurring [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative instruments - short-term	39.4	188.7	'	'
Derivative instruments - long-term	5.8	4.1	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	7.6	0	'	'
Derivative instruments - long-term	'	0	'	'
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	2.5	2.6	'	'
Derivative instruments - long-term	'	3.6	'	'
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Checks outstanding in excess of cash balances	1.6	39.7	'	'
Long-term debt	2,882.30	3,206.90	'	'
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]	'	'	'	'
Financial Assets	'	'	'	'
Total financial assets	0	0	'	'
Financial liabilities	'	'	'	'
Total financial liabilities	0	0	'	'
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	0	0	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	'	0	'	'
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest Rate Swap [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	'	0	'	'
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Fair Value [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Checks outstanding in excess of cash balances	1.6	39.7	'	'
Long-term debt	2,900.50	3,420.70	'	'
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]	'	'	'	'
Financial Assets	'	'	'	'
Total financial assets	63.8	193.9	'	'
Financial liabilities	'	'	'	'
Total financial liabilities	28.7	7.3	'	'
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative instruments - short-term	'	189.7	'	'
Derivative instruments - long-term	'	4.2	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	26.2	1	'	'
Derivative instruments - long-term	'	0.1	'	'
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	2.5	2.6	'	'
Derivative instruments - long-term	'	3.6	'	'
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]	'	'	'	'
Financial Assets	'	'	'	'
Total financial assets	0	0	'	'
Financial liabilities	'	'	'	'
Total financial liabilities	0	0	'	'
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	0	0	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	'	0	'	'
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest Rate Swap [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	'	0	'	'
Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]	'	'	'	'
Financial Assets	'	'	'	'
Total financial assets	-18.6	-1.1	'	'
Financial liabilities	'	'	'	'
Total financial liabilities	-18.6	-1.1	'	'
Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative instruments - short-term	-18.6	-1	'	'
Derivative instruments - long-term	0	-0.1	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	-18.6	-1	'	'
Derivative instruments - long-term	'	-0.1	'	'
Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member] | Interest Rate Swap [Member]	'	'	'	'
Financial liabilities	'	'	'	'
Derivative instruments - short-term	0	0	'	'
Derivative instruments - long-term	'	0	'	'
Long-term [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative Asset, Fair Value, Gross	'	4.2	'	'
Long-term [Member] | Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative Asset, Fair Value, Gross	5.8	'	'	'
Short-term [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative Asset, Fair Value, Gross	'	189.7	'	'
Short-term [Member] | Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commodity Contract [Member]	'	'	'	'
Financial Assets	'	'	'	'
Derivative Asset, Fair Value, Gross	$58	'	'	'

Derivative_Contracts_Details

Derivative Contracts (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'		'		'		'		'
Forecasted production from proved reserves (in hundredths)	'		'		100.00%		'		'
Unrealized gains on derivative contracts	$27.30		'		$27.30		'		'
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	17.2		'		17.2		'		'
Notional amount of interest rate derivatives	300		'		300		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Total principal amount of debt	2,886.80		'		2,886.80		'		3,211.80
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Notional amount of interest rate derivatives	300		'		300		'		'
Fair Value of Derivative Contracts, Gross [Abstract]	'		'		'		'		'
Derivative Asset, Fair Value, Gross	63.8		'		63.8		'		193.9
Derivative Liability, Fair Value, Gross	28.7		'		28.7		'		7.3
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	-19.7	[1]	-42.1	[1]	-60.4	[1]	-133.8	[1]	'
Commodity Contract [Member] | Short-term [Member]	'		'		'		'		'
Fair Value of Derivative Contracts, Gross [Abstract]	'		'		'		'		'
Derivative Asset, Fair Value, Gross	'		'		'		'		189.7
Derivative Liability, Fair Value, Gross	26.2		'		26.2		'		1
Commodity Contract [Member] | Long-term [Member]	'		'		'		'		'
Fair Value of Derivative Contracts, Gross [Abstract]	'		'		'		'		'
Derivative Asset, Fair Value, Gross	'		'		'		'		4.2
Derivative Liability, Fair Value, Gross	0		'		0		'		0.1
Interest Rate Swap [Member] | Short-term [Member]	'		'		'		'		'
Fair Value of Derivative Contracts, Gross [Abstract]	'		'		'		'		'
Derivative Asset, Fair Value, Gross	0		'		0		'		0
Derivative Liability, Fair Value, Gross	2.5		'		2.5		'		2.6
Interest Rate Swap [Member] | Long-term [Member]	'		'		'		'		'
Fair Value of Derivative Contracts, Gross [Abstract]	'		'		'		'		'
Derivative Asset, Fair Value, Gross	0		'		0		'		0
Derivative Liability, Fair Value, Gross	0		'		0		'		3.6
Swap [Member] | Natural Gas Sales (MMbtu) [Member] | 2013 [Member] | NYMEX [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2013		'		'
Index	'		'		'NYMEX		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	14,700,000		'		14,700,000		'		'
Average Swap price per unit ($ per unit)	3.81		'		3.81		'		'
Swap [Member] | Natural Gas Sales (MMbtu) [Member] | 2013 [Member] | IFNPCR [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2013		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	18,400,000		'		18,400,000		'		'
Average Swap price per unit ($ per unit)	5.49		'		5.49		'		'
Swap [Member] | Natural Gas Sales (MMbtu) [Member] | 2014 [Member] | NYMEX [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2014		'		'
Index	'		'		'NYMEX		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	25,600,000		'		25,600,000		'		'
Average Swap price per unit ($ per unit)	4.19		'		4.19		'		'
Swap [Member] | Natural Gas Sales (MMbtu) [Member] | 2014 [Member] | IFNPCR [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2014		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	32,900,000		'		32,900,000		'		'
Average Swap price per unit ($ per unit)	4		'		4		'		'
Swap [Member] | Oil Sales (Bbls) [Member] | 2013 [Member] | NYMEX WTI [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2013		'		'
Index	'		'		'NYMEX WTI		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	2,100,000		'		2,100,000		'		'
Average Swap price per unit ($ per unit)	98.27		'		98.27		'		'
Swap [Member] | Oil Sales (Bbls) [Member] | 2013 [Member] | BRENT ICE [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2013		'		'
Index	'		'		'BRENT ICE		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	100,000		'		100,000		'		'
Average Swap price per unit ($ per unit)	107.8		'		107.8		'		'
Swap [Member] | Oil Sales (Bbls) [Member] | 2014 [Member] | NYMEX WTI [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2014		'		'
Index	'		'		'NYMEX WTI		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	8,800,000		'		8,800,000		'		'
Average Swap price per unit ($ per unit)	93.63		'		93.63		'		'
Swap [Member] | QEP Marketing [Member] | 2013 [Member] | IFNPCR [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2013		'		'
Index	'		'		'IFNPCR		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	1,600,000		'		1,600,000		'		'
Average Swap price per unit ($ per unit)	3.91		'		3.91		'		'
Swap [Member] | QEP Marketing [Member] | 2014 [Member] | IFNPCR [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2014		'		'
Index	'		'		'IFNPCR		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	3,800,000		'		3,800,000		'		'
Average Swap price per unit ($ per unit)	3.71		'		3.71		'		'
Swap [Member] | QEP Resources [Member]	'		'		'		'		'
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'		'		'		'		'
Notional amount of interest rate derivatives	300		'		300		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Notional amount of interest rate derivatives	300		'		300		'		'
Maturity	'		'		31-Mar-17		'		'
Fixed Rate Paid (in hundredths)	1.07%		'		1.07%		'		'
Variable Rate Received	'		'		'One month LIBOR		'		'
Swap [Member] | Purchased Gas and Oil Expense [Member] | 2013 [Member] | IFNPCR [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2013		'		'
Index	'		'		'IFNPCR		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	1,700,000		'		1,700,000		'		'
Average Swap price per unit ($ per unit)	3.46		'		3.46		'		'
Swap [Member] | Purchased Gas and Oil Expense [Member] | 2014 [Member] | IFNPCR [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Year	'		'		'2014		'		'
Index	'		'		'IFNPCR		'		'
Derivative Contracts - Volumes and Prices	'		'		'		'		'
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	200,000		'		200,000		'		'
Average Swap price per unit ($ per unit)	3.82		'		3.82		'		'
Term Loan due 2017 [Member]	'		'		'		'		'
Derivatives, Fair Value [Line Items]	'		'		'		'		'
Total principal amount of debt	$300		'		$300		'		$300
[1]	Presented net of income tax benefit of $11.7 million and $35.8 million during the three and nine months ended SeptemberB 30, 2013 and $24.9 million and $79.2 million during the three and nine months ended SeptemberB 30, 2012, respectively.

Derivative_Contracts_Gain_Loss

Derivative Contracts - Gain (Loss) in Statement of Financial Performance (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) derivative contracts not designated as hedging instruments	$26.30	$93.20	$107.10	$301.90
Unrealized gain (loss) derivative contracts not designated as hedging instruments	-54.1	-57.1	-55.5	32.8
Total gain (loss) on commodity derivative instruments	'	'	51.6	334.7
Natural gas derivative contracts [Member] | QEP Energy [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	42.5	86.2	112	283.8
Unrealized gain (loss) on commodity derivative contracts	-6.6	-50.6	-9.6	3.3
Natural gas derivative contracts [Member] | QEP Marketing [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	-0.3	-0.4	0.7	3.7
Unrealized gain (loss) on commodity derivative contracts	0.1	-1.4	-0.3	-0.5
Oil derivative contracts [Member] | QEP Energy [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	-15.3	2.7	-3.7	2.2
Unrealized gain (loss) on commodity derivative contracts	-46.2	4.1	-49.1	31.2
NGL derivative contracts [Member] | QEP Energy [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	0	3.4	0	6.5
Unrealized gain (loss) on commodity derivative contracts	0	-4.4	0	3.4
NGL derivative contracts [Member] | QEP Field Services [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	0	1.9	0	6.3
Unrealized gain (loss) on commodity derivative contracts	0	-2.5	0	2
Interest Rate Swap [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	-0.6	-0.6	-1.9	-0.6
Unrealized gain (loss) on commodity derivative contracts	-1.4	-2.3	3.5	-6.6
Realized and Unrealized Gain (Loss) on Commodity Derivative Contracts Not Designated as Hedging Instruments	-2	-2.9	1.6	-7.2
Total gain (loss) on commodity derivative instruments	-27.8	36.1	'	'
Realized and unrealized gains on commodity derivative instruments [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments [Abstract]	'	'	'	'
Realized gain (loss) on commodity derivative contracts	26.9	93.8	109	302.5
Unrealized gain (loss) on commodity derivative contracts	-52.7	-54.8	-59	39.4
Total gain (loss) on commodity derivative instruments	($25.80)	$39	$50	$341.90

Restructuring_Costs_Details

Restructuring Costs (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	$8	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	7.9	'
Restructuring Charges	0.3	0.3	0.9	5.3
Increase (Decrease) in Restructuring Liability [Roll Forward]	'	'	'	'
Balance at Beginning of Period	'	'	1	'
Restructuring Reserve, Accrual Adjustment	'	'	0.9	'
Costs paid or otherwise settled	'	'	-1.9	'
Balance at End of Period	0	'	0	'
Number of regional offices created	'	'	1	'
One-time Termination Benefits [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	3.6	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	3.6	'
Restructuring Charges	0.1	0.2	0.5	2.1
Employee Relocation [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	3.8	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	3.7	'
Restructuring Charges	0.2	0.1	0.4	3.2
Termination of Lease [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0.6	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0.6	'
Restructuring Charges	0	0	0	0
QEP Energy [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	7.6	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	7.5	'
Restructuring Charges	0.2	0.3	0.7	5.3
Increase (Decrease) in Restructuring Liability [Roll Forward]	'	'	'	'
Balance at Beginning of Period	'	'	1	'
Restructuring Reserve, Accrual Adjustment	'	'	0.7	'
Costs paid or otherwise settled	'	'	-1.7	'
Balance at End of Period	0	'	0	'
QEP Energy [Member] | One-time Termination Benefits [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	3.3	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	3.3	'
Restructuring Charges	0.1	0.2	0.4	2.1
QEP Energy [Member] | Employee Relocation [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	3.7	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	3.6	'
Restructuring Charges	0.1	0.1	0.3	3.2
QEP Energy [Member] | Termination of Lease [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0.6	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0.6	'
Restructuring Charges	0	0	0	0
QEP Field Services [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0.1	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0.1	'
Restructuring Charges	0.1	0	0.1	0
Increase (Decrease) in Restructuring Liability [Roll Forward]	'	'	'	'
Balance at Beginning of Period	'	'	0	'
Restructuring Reserve, Accrual Adjustment	'	'	0.1	'
Costs paid or otherwise settled	'	'	-0.1	'
Balance at End of Period	0	'	0	'
QEP Field Services [Member] | One-time Termination Benefits [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0	'
Restructuring Charges	0	0	0	0
QEP Field Services [Member] | Employee Relocation [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0.1	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0.1	'
Restructuring Charges	0.1	0	0.1	0
QEP Field Services [Member] | Termination of Lease [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0	'
Restructuring Charges	0	0	0	0
QEP Marketing [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0.3	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0.3	'
Restructuring Charges	0	0	0.1	0
Increase (Decrease) in Restructuring Liability [Roll Forward]	'	'	'	'
Balance at Beginning of Period	'	'	0	'
Restructuring Reserve, Accrual Adjustment	'	'	0.1	'
Costs paid or otherwise settled	'	'	-0.1	'
Balance at End of Period	0	'	0	'
QEP Marketing [Member] | One-time Termination Benefits [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0.3	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0.3	'
Restructuring Charges	0	0	0.1	0
QEP Marketing [Member] | Employee Relocation [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0	'
Restructuring Charges	0	0	0	0
QEP Marketing [Member] | Termination of Lease [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated restructuring costs	'	'	0	'
Restructuring and Related Cost, Cost Incurred to Date	'	'	0	'
Restructuring Charges	$0	$0	$0	$0

Debt_Details

Debt (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	$2,886.80	$3,211.80	'
Less unamortized discount	-4.5	-4.9	'
Total long-term debt outstanding	2,882.30	3,206.90	'
Principal amount of senior notes outstanding	2,221.80	'	'
Debt Instrument, Maturity Date Range, Start	1-Sep-16	'	'
Debt Instrument, Maturity Date Range, End	1-May-23	'	'
Senior Notes, stated interest rate, minimum (in hundredths)	5.25%	'	'
Senior Notes, stated interest rate, maximim (in hundredths)	6.88%	'	'
Revolving Credit Facility due 2016 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	365	690	'
Maturity date of long-term debt	25-Aug-16	'	'
Borrowing capacity	1,500	'	'
Potential increased borrowing capacity	2,000	'	'
Number of maturity date extentions	2	'	'
Additional period with in which maturity to be extended	'1 year	'	'
Weighted-average interest rate (in hundredths)	2.56%	'	2.05%
Amount outstanding	365	'	'
Letters of credit outstanding	3.7	'	'
QEP Midstream's Credit Facility [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	0	0	'
Maturity date of long-term debt	14-Aug-18	'	'
Borrowing capacity	500	'	'
Potential increased borrowing capacity	750	'	'
Term Loan due 2017 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	300	300	'
Maturity date of long-term debt	18-Apr-17	'	'
Additional period with in which maturity to be extended	'1 year	'	'
Weighted-average interest rate (in hundredths)	2.23%	'	2.02%
6.05% Senior Notes due 2016 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	176.8	176.8	'
Long-term debt, interest rate (in hundredths)	6.05%	'	'
Maturity date of long-term debt	1-Sep-16	'	'
Maturity period of long-term debt	'5 years	'	'
6.80% Senior Notes due 2018 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	134	134	'
Long-term debt, interest rate (in hundredths)	6.80%	'	'
Maturity date of long-term debt	1-Apr-18	'	'
6.80% Senior Notes due 2020 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	136	136	'
6.875% Senior Notes due 2021 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	625	625	'
5.375% Senior Notes due 2022 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	500	500	'
5.25% Senior Notes Due 2023 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Total principal amount of debt	$650	$650	'

Schedule_of_Contingencies_Deta

Schedule of Contingencies (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Accrual for Environmental Loss Contingencies, Payments	$0
Loss Contingency, Settlement Agreement, Consideration	115
Deferred Revenue	$7

ShareBased_Compensation_Detail

Share-Based Compensation (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation [Abstract]	'	'	'	'
Shares available for future grants	11,900,000	'	11,900,000	'
Weighted-Average Price [Abstract]	'	'	'	'
Share-based compensation	$6.80	$7.20	$20	$19.50
Stock Options [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Fair value of options at grant date	'	'	$15.16	'
Risk-free interest rate (in hundredths)	'	'	1.00%	'
Expected price volatility (in hundredths)	'	'	58.30%	'
Expected dividend yield (in hundredths)	'	'	0.27%	'
Expected life in years	'	'	'5 years 6 months	'
Options Outstanding [RollForward]	'	'	'	'
Outstanding Beginning Balance (in shares)	'	'	1,697,471	'
Granted (in shares)	'	'	330,592	'
Exercised (in shares)	'	'	-209,500	'
Forfeited (in shares)	'	'	0	'
Outstanding Ending Balance (in shares)	1,818,563	'	1,818,563	'
Options Excercisable (in shares)	1,236,211	'	1,236,211	'
Unvested Options (in shares)	582,352	'	582,352	'
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	'	'	1.4	2.2
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	'	'	1.4	'
Weighted-Average Price [Abstract]	'	'	'	'
Weighted-Average Price, beginning (in dollars per share)	'	'	$25.23	'
Weighted-Average Price, Granted (in dollars per share)	'	'	$30.06	'
Weighted-Average Price, Exercised (in dollars per share)	'	'	$9.60	'
Weighted-Average Price, Forfeited (in dollars per share)	'	'	$0	'
Weighted-Average Price, Ending (in dollars per share)	$27.90	'	$27.90	'
Weighted-Average Price, Options Excercisable	$26.36	'	$26.36	'
Weighted-Average Price, Unvested Options	$31.18	'	$31.18	'
Weighted-Average Remaining Contractual Term, Outstanding	'	'	'3 years 10 months 24 days	'
Aggregate Intrinsic Value, Outstanding	3.6	'	3.6	'
Weighted-Average Remaining Contractual Term, Options Excercisable	'	'	'3 years 0 months 0 days	'
Aggregate Intrinsic Value, Options Excercisable	3.6	'	3.6	'
Weighted-Average Remaining Contractual Term, Unvested Options	'	'	'5 years 10 months 24 days	'
Aggregate Intrinsic Value, Unvested Options	0	'	0	'
Intrinsic value of options exercised	'	'	4.2	7.1
Unrecognized compensation cost	4.4	'	4.4	'
Weighted-average period for recognition of compensation costs	'	'	'2 years 1 month 24 days	'
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	'	'	0.5	'
Restricted Stock [Member]	'	'	'	'
Options Outstanding [RollForward]	'	'	'	'
Total fair value of stock that vested	'	'	18.4	16.6
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	'	'	-0.4	-0.2
Restricted Shares Outstanding [Roll Forward]	'	'	'	'
Balance, beginning (in shares)	'	'	1,300,588	'
Granted (in shares)	'	'	850,824	'
Vested (in shares)	'	'	-620,065	'
Forfeited (in shares)	'	'	-75,442	'
Balance, Ending (in shares)	1,455,905	'	1,455,905	'
Weighted-Average Price [Abstract]	'	'	'	'
Weighted-Average Price, beginning balance (in dollars per share)	'	'	$31.78	'
Weighted-Average Price, Granted (in dollars per share)	'	'	$30.03	$30.59
Weighted-Average Price, Vested (in dollars per share)	'	'	$31.42	'
Weighted-Average Price, Forfeited (in dollars per share)	'	'	$30.82	'
Weighted-Average Price, Ending Balance (in dollars per share)	$30.96	'	$30.96	'
Unrecognized compensation cost	23.5	'	23.5	'
Weighted-average period for recognition of compensation costs	'	'	'2 years 2 months 4 days	'
Restricted Stock [Member] | Minimum [Member]	'	'	'	'
Weighted-Average Price [Abstract]	'	'	'	'
Vesting period (in years)	'	'	'3 years 0 months 0 days	'
Performance Share Units [Member]	'	'	'	'
Restricted Shares Outstanding [Roll Forward]	'	'	'	'
Balance, beginning (in shares)	'	'	283,484	'
Granted (in shares)	'	'	223,844	'
Vested (in shares)	'	'	0	'
Forfeited (in shares)	'	'	-1,163	'
Balance, Ending (in shares)	506,165	'	506,165	'
Weighted-Average Price [Abstract]	'	'	'	'
Weighted-Average Price, beginning balance (in dollars per share)	'	'	$34.01	'
Weighted-Average Price, Granted (in dollars per share)	'	'	$30.12	$30.90
Weighted-Average Price, Vested (in dollars per share)	'	'	$0	'
Weighted-Average Price, Forfeited (in dollars per share)	'	'	($30.12)	'
Weighted-Average Price, Ending Balance (in dollars per share)	$32.30	'	$32.30	'
Unrecognized compensation cost	8.5	'	8.5	'
Weighted-average period for recognition of compensation costs	'	'	'2 years 0 months 0 days	'
QEP Midstream Long-Term Incentive Plan [Member]	'	'	'	'
Weighted-Average Price [Abstract]	'	'	'	'
Share-based compensation	'	'	$0.10	'

Employee_Benefits_Details

Employee Benefits (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension [Member]	'	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'
Service cost	$0.70	$1.10	$2.60	$3
Interest cost	1.2	1.3	3.7	3.7
Expected return on plan assets	-0.9	-0.9	-2.9	-2.7
Amortization of prior service costs	1.2	1.3	3.7	3.9
Amortization of actuarial loss	0.5	0.6	1.7	1
Periodic expense	2.7	3.4	8.8	8.9
Pension [Member] | Funded Pension Plan [Member]	'	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'
Contributions to pension plan	'	'	8.1	'
Pension [Member] | Unfunded Pension Plan [Member]	'	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'
Contributions to pension plan	'	'	2.7	'
Expected to contribute to pension plans	0.4	'	0.4	'
Pension [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'
Expected to contribute to pension plans	0.1	'	0.1	'
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'
Service cost	0.1	0.1	0.1	0.1
Interest cost	0	0	0.2	0.2
Amortization of prior service costs	0.1	0.1	0.3	0.3
Amortization of actuarial loss	0.1	0	0.1	0
Periodic expense	$0.30	$0.20	$0.70	$0.60

Operations_by_Line_of_Business2

Operations by Line of Business (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	'	'	'	'
Total Revenues	$772.80	$542.40	$2,220.30	$1,644.90
Operating expenses	'	'	'	'
Purchased gas, oil and NGL expense	205	142.6	608.8	455.9
Lease operating expense	45	42.2	127.4	122.8
Natural gas, oil and NGL transportation and other handling costs	34.5	36.3	105.8	111.5
Gathering, processing and other	22.4	22.1	66.5	66.4
General and administrative	49.3	41.7	136.2	114.5
Production and property taxes	42.5	24.3	117.7	68.4
Depreciation, depletion and amortization	253.1	234.6	757.1	648.3
Other operating expenses	5.6	11.2	13.5	77.2
Total Operating Expenses	657.4	555	1,933	1,665
Net (loss) gain from asset sales	12.8	0	113	1.5
Operating (loss) income	128.2	-12.6	400.3	-18.6
Realized and unrealized gains (losses) on derivative contracts	-27.8	36.1	51.6	334.7
Interest and other income	4	-0.2	9.1	2.4
Income from unconsolidated affiliates	0.8	2.3	3.7	5.6
Loss from early extinguishment of debt	0	0	0	-0.6
Interest expense	-41.7	-30	-122.5	-82.9
Income (loss) before income taxes	63.5	-4.4	342.2	240.6
Income taxes	-22.4	2.3	-125	-86.5
Net (loss) income	41.1	-2.1	217.2	154.1
Net income attributable to noncontrolling interest	-3.8	-1	-5.8	-2.7
Net income (loss) attributable to QEP	37.3	-3.1	211.4	151.4
Unaffiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	772.8	542.4	2,220.30	1,644.90
Affiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	0	0	0	0
QEP Energy [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	538.5	374	1,575.20	1,106.30
Operating expenses	'	'	'	'
Purchased gas, oil and NGL expense	39.2	45.9	159.8	159
Lease operating expense	43.5	43.1	130.2	125.3
Natural gas, oil and NGL transportation and other handling costs	65.1	59.8	180.8	167.4
Gathering, processing and other	0	0	0	0
General and administrative	33.5	31.6	100.2	92.7
Production and property taxes	40.4	22.5	112.7	63.6
Depreciation, depletion and amortization	236	218.5	712.1	600.2
Other operating expenses	5.6	11.2	13.5	77.2
Total Operating Expenses	463.3	432.6	1,409.30	1,285.40
Net (loss) gain from asset sales	12.8	'	113.4	1.5
Operating (loss) income	88	-58.6	279.3	-177.6
Realized and unrealized gains (losses) on derivative contracts	-25.6	41.4	49.6	330.4
Interest and other income	2.6	-0.2	7.5	2.2
Income from unconsolidated affiliates	0	0	0	0.1
Loss from early extinguishment of debt	'	0	'	0
Interest expense	-49.2	-24.1	-143.4	-71.1
Income (loss) before income taxes	15.8	-41.5	193	84
Income taxes	-6.2	15.3	-71.1	-32.4
Net (loss) income	9.6	-26.2	121.9	51.6
Net income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to QEP	9.6	-26.2	121.9	51.6
QEP Energy [Member] | Unaffiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	538.5	374	1,575.20	1,106.30
QEP Energy [Member] | Affiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	0	0	0	0
QEP Field Services [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	100.1	109.7	295	343
Operating expenses	'	'	'	'
Purchased gas, oil and NGL expense	0	4.9	8.6	9
Lease operating expense	0	0	0	0
Natural gas, oil and NGL transportation and other handling costs	3.4	6.9	11.6	27.7
Gathering, processing and other	22	21.8	65.3	65.6
General and administrative	15.8	10.5	36.2	23.7
Production and property taxes	2	1.7	4.8	4.6
Depreciation, depletion and amortization	16.8	15.9	44.3	47.6
Other operating expenses	0	0	0	0
Total Operating Expenses	60	61.7	170.8	178.2
Net (loss) gain from asset sales	0	'	-0.4	0
Operating (loss) income	40.1	48	123.8	164.8
Realized and unrealized gains (losses) on derivative contracts	0	-0.6	0	8.3
Interest and other income	0.8	0	1.1	0.1
Income from unconsolidated affiliates	0.8	2.3	3.7	5.5
Loss from early extinguishment of debt	'	0	'	0
Interest expense	-3.2	-3.5	-12.5	-9.4
Income (loss) before income taxes	38.5	46.2	116.1	169.3
Income taxes	-12.7	-16.5	-40.3	-59.2
Net (loss) income	25.8	29.7	75.8	110.1
Net income attributable to noncontrolling interest	-3.8	-1	-5.8	-2.7
Net income (loss) attributable to QEP	22	28.7	70	107.4
QEP Field Services [Member] | Unaffiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	66.9	77.9	203.6	254.9
QEP Field Services [Member] | Affiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	33.2	31.8	91.4	88.1
QEP Marketing and Other [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	440.2	236.3	1,153.20	680
Operating expenses	'	'	'	'
Purchased gas, oil and NGL expense	438.2	236.7	1,150.60	681.7
Lease operating expense	0	0	0	0
Natural gas, oil and NGL transportation and other handling costs	0	0	0	0
Gathering, processing and other	0.4	0.1	1.2	0.8
General and administrative	1.1	1.2	3.3	2.6
Production and property taxes	0.1	0.1	0.2	0.2
Depreciation, depletion and amortization	0.3	0.2	0.7	0.5
Other operating expenses	0	0	0	0
Total Operating Expenses	440.1	238.3	1,156	685.8
Net (loss) gain from asset sales	0	'	0	0
Operating (loss) income	0.1	-2	-2.8	-5.8
Realized and unrealized gains (losses) on derivative contracts	-2.2	-4.7	2	-4
Interest and other income	52.3	28.4	158.2	81.1
Income from unconsolidated affiliates	0	0	0	0
Loss from early extinguishment of debt	'	0	'	-0.6
Interest expense	-41	-30.8	-124.3	-83.4
Income (loss) before income taxes	9.2	-9.1	33.1	-12.7
Income taxes	-3.5	3.5	-13.6	5.1
Net (loss) income	5.7	-5.6	19.5	-7.6
Net income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to QEP	5.7	-5.6	19.5	-7.6
QEP Marketing and Other [Member] | Unaffiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	167.4	90.5	441.5	283.7
QEP Marketing and Other [Member] | Affiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	272.8	145.8	711.7	396.3
Elimination [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	-306	-177.6	-803.1	-484.4
Operating expenses	'	'	'	'
Purchased gas, oil and NGL expense	-272.4	-144.9	-710.2	-393.8
Lease operating expense	1.5	-0.9	-2.8	-2.5
Natural gas, oil and NGL transportation and other handling costs	-34	-30.4	-86.6	-83.6
Gathering, processing and other	0	0.2	0	0
General and administrative	-1.1	-1.6	-3.5	-4.5
Production and property taxes	0	0	0	0
Depreciation, depletion and amortization	0	0	0	0
Other operating expenses	0	0	0	0
Total Operating Expenses	-306	-177.6	-803.1	-484.4
Net (loss) gain from asset sales	0	'	0	0
Operating (loss) income	0	0	0	0
Realized and unrealized gains (losses) on derivative contracts	0	0	0	0
Interest and other income	-51.7	-28.4	-157.7	-81
Income from unconsolidated affiliates	0	0	0	0
Loss from early extinguishment of debt	'	0	'	0
Interest expense	51.7	28.4	157.7	81
Income (loss) before income taxes	0	0	0	0
Income taxes	0	0	0	0
Net (loss) income	0	0	0	0
Net income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to QEP	0	0	0	0
Elimination [Member] | Unaffiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	0	0	0	0
Elimination [Member] | Affiliated customers [Member]	'	'	'	'
Revenues	'	'	'	'
Total Revenues	($306)	($177.60)	($803.10)	($484.40)