Quarterly Financial Information (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 799.6	$ 910.0	$ 887.2	$ 817.5	$ 620.3	$ 719.5	$ 694.0	$ 651.3	$ 3,414.3	$ 2,685.1	$ 2,071.7
OPERATING INCOME (LOSS)	(1,067.3)	115.1	(35.9)	140.8	(66.7)	83.3	159.1	27.3	(847.3)	203.0	(321.2)
Income (loss) from continuing operations	(469.8)	153.7	(106.1)	12.7	(84.4)	12.1	149.2	(24.8)	(409.5)	52.1	2.4
Net income from discontinued operations, net of income tax	1,135.7	17.4	13.8	27.0	32.4	25.2	29.2	20.5	1,193.9	107.3	125.9
Net income attributable to QEP	665.9	171.1	(92.3)	39.7	(52.0)	37.3	178.4	(4.3)	784.4	159.4	128.3
Non-recurring income(loss)	$ (1,077.8)	$ (11.9)	$ (202.5)	$ 0.4	$ (98.5)	$ 9.0	$ 100.2	$ (0.2)	$ (1,291.8)	$ 10.5
Basic total									$ 4.36	$ 0.89	$ 0.72
Diluted total									$ 4.36	$ 0.89	$ 0.72
Continuing Operations [Member]
Effect of Fourth Quarter Events [Line Items]
Basic total	$ (2.62)	$ 0.85	$ (0.59)	$ 0.07	$ (0.47)	$ 0.07	$ 0.83	$ (0.14)	$ (2.28)	$ 0.29	$ 0.01
Diluted total	$ (2.62)	$ 0.84	$ (0.59)	$ 0.07	$ (0.47)	$ 0.07	$ 0.83	$ (0.14)	$ (2.28)	$ 0.29	$ 0.01
Discontinued Operations [Member]
Effect of Fourth Quarter Events [Line Items]
Basic total	$ 6.34	$ 0.10	$ 0.08	$ 0.15	$ 0.18	$ 0.14	$ 0.16	$ 0.12	$ 6.64	$ 0.60	$ 0.71
Diluted total	$ 6.34	$ 0.10	$ 0.08	$ 0.15	$ 0.18	$ 0.14	$ 0.16	$ 0.12	$ 6.64	$ 0.60	$ 0.71