Basis of Presentation of Interim Financial Statements (Tables)

3 Months Ended

Mar. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Cost of sales detail

The details of Questar's consolidated cost of sales are as follows:

	3 Months Ended						12 Months Ended
	March 31,						March 31,
	2016			2015			2016			2015
	(in millions)
Questar Gas
Gas purchases	$	46.8		$	41.0		$	88.3		$	84.8
Operator service fee	79.8			84.8			314.0			345.4
Transportation and storage	22.3			22.2			79.3			79.7
Gathering	5.8			5.4			22.5			21.5
Royalties	5.7			11.9			27.1			54.7
Storage (injection) withdrawal, net	36.7			30.9			2.3			(3.2		)
Purchased-gas account adjustment	58.6			36.2			42.9			(4.0		)
Other	1.2			1.2			5.0			4.9
Total Questar Gas cost of natural gas sold	256.9			233.6			581.4			583.8
Elimination of Questar Gas cost of natural gas sold - affiliated companies	(99.0		)	(104.0		)	(388.5		)	(419.2		)
Total Questar Gas cost of natural gas sold - unaffiliated parties	157.9			129.6			192.9			164.6
Questar Pipeline
Questar Pipeline cost of sales	0.1			1.9			7.1			4.2
Other cost of sales	0.5			0.3			1.9			1.1
Total cost of sales	$	158.5		$	131.8		$	201.9		$	169.9