Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Restricted Cash and Cash Equivalents Items [Line Items]

Restrictions on Cash and Cash Equivalents [Table Text Block]

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets to the amounts shown in the Consolidated Statements of Cash Flows:

	December 31,
	2018		2017
	(in millions)
Cash and cash equivalents	$	—	$	—
Restricted cash(1)	28.1		23.4
Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows	$	28.1	$	23.4

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⁽¹⁾  As of December 31, 2018 and 2017, the restricted cash balance related to cash deposited into an escrow account for a title dispute between outside parties in the Williston Basin, and the restricted cash balance is recorded within "Other noncurrent assets" on the Consolidated Balance Sheets.

Supplemental Cash Flow Information [Table Text Block]

Supplemental cash flow information is shown in the table below:

	Year Ended December 31,
	2018			2017			2016
Supplemental Disclosures:	(in millions)
Cash paid for interest, net of capitalized interest	$	136.9		$	134.9		$	139.1
Cash paid (refund received) for income taxes, net	$	0.8		$	(0.3	)	$	(123.5	)
Non-cash Investing Activities:
Change in capital expenditure accrual balance	$	(57.4	)	$	60.2		$	(32.8	)

Property, Plant and Equipment [Table Text Block]

DD&A for the Company's remaining properties is generally based upon rates that will systematically charge the costs of assets against income over the estimated useful lives of those assets using the straight-line method. The estimated useful lives of those assets depreciated under the straight-line basis generally range as follows:

Buildings	10 to 30 years
Leasehold improvements	3 to 10 years
Service, transportation and field service equipment	3 to 7 years
Furniture and office equipment	3 to 7 years

Credit Risk [Policy Text Block]

The following table presents the percentages by customer that accounted for 10% or more of QEP's total revenues.

Year Ended December 31, 2018
Occidental Energy Marketing	16	%
Plains Marketing LP	12	%
Year Ended December 31, 2017
Shell Trading Company	14	%
Occidental Energy Marketing	13	%
Andeavor Logistics LP	13	%
BP Energy Company	10	%
Plains Marketing LP	10	%
Year Ended December 31, 2016
Shell Trading Company	14	%
BP Energy Company	10	%
Valero Marketing & Supply Company	10	%

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

The following is a reconciliation of the components of basic and diluted shares used in the EPS calculation:

	December 31,
	2018	2017	2016
	(in millions)
Weighted-average basic common shares outstanding	237.9	240.6	221.7
Potential number of shares issuable upon exercise of in-the-money stock options under the Long-Term Stock Incentive Plan	—	—	—
Average diluted common shares outstanding	237.9	240.6	221.7