Share-Based Compensation Stock options (Details) (Stock Options [Member], USD $)	3 Months Ended
	Mar. 31, 2014
Stock option transactions under the terms of the LTSIP - shares [Roll Forward]
Granted	0
Exercised	0
Forfeited	0
Stock option transactions under the terms of the LTSIP - exercise price [Roll Forward]
Balance at March 31, 2014	$ 11.84
Stock options outstanding, exercisable and unvested at end of period, by exercise price range [Abstract]
Options Outstanding, Number outstanding at end of period	717,840
Options Outstanding, Weighted-average remaining term (in years and months)	1 year 11 months
Options Exercisable, Number exercisable at end of period	717,840
Options Exercisable, Weighted-average exercise price	$ 11.84
Stock options, additional disclosures [Abstract]
Number of unvested options at end of period (in shares)	0
Number of Questar stock options held by certain officers, employees and nonemployee directors of QEP (in shares)	251,098
Weighted-average exercise price of Questar stock options awarded to certain officers, employees and nonemployee directors of QEP (in dollars per share)	$ 11.33
Weighted-average remaining life of Questar stock options held by certain officers, employees and nonemployee directors of QEP (in years)	2 years 2 months
$7.84 - $11.40 [Member]
Stock option transactions under the terms of the LTSIP - exercise price [Roll Forward]
Balance at March 31, 2014	$ 10.52
Stock options outstanding, exercisable and unvested at end of period, by exercise price range [Abstract]
Range of exercise prices, lower limit	$ 7.84
Range of exercise prices, upper limit	$ 11.40
Options Outstanding, Number outstanding at end of period	404,174
Options Outstanding, Weighted-average remaining term (in years and months)	1 year 7 months
Options Exercisable, Number exercisable at end of period	404,174
Options Exercisable, Weighted-average exercise price	$ 10.52
$13.10 - $17.35 [Member]
Stock option transactions under the terms of the LTSIP - exercise price [Roll Forward]
Balance at March 31, 2014	$ 13.54
Stock options outstanding, exercisable and unvested at end of period, by exercise price range [Abstract]
Range of exercise prices, lower limit	$ 13.10
Range of exercise prices, upper limit	$ 17.35
Options Outstanding, Number outstanding at end of period	313,666
Options Outstanding, Weighted-average remaining term (in years and months)	2 years 3 months
Options Exercisable, Number exercisable at end of period	313,666
Options Exercisable, Weighted-average exercise price	$ 13.54