Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2011

Disclosure of fair value and related carrying amount of certain financial instruments

The following tables disclose the carrying amount and related fair value of certain financial instruments not disclosed in other notes to the financial statements in this Quarterly Report on Form 10-Q:

Questar

	Carrying		Estimated		Carrying		Estimated		Carrying		Estimated
	Amount		Fair Value		Amount		Fair Value		Amount		Fair Value
	Sept. 30, 2011				Sept. 30, 2010				Dec. 31, 2010
	(in millions)
Financial assets
Cash and cash equivalents	$	-	$	-	$	-	$	-	$	21.8	$	21.8
Long-term investment		14.1		14.1		12.9		12.9		13.1		13.1
Financial liabilities
Checks outstanding in excess of cash balances		9.6		9.6		5.4		5.4		-		-
Short-term debt		278.0		278.0		395.0		395.0		242.0		242.0
Long-term debt, including current portion	$	906.4	$	1,013.9	$	831.1	$	956.7	$	1,080.5	$	1,173.8

Questar Pipeline

	Carrying		Estimated		Carrying		Estimated		Carrying		Estimated
	Amount		Fair Value		Amount		Fair Value		Amount		Fair Value
	Sept. 30, 2011				Sept. 30, 2010				Dec. 31, 2010
	(in millions)
Financial assets
Cash and cash equivalents	$	0.4	$	0.4	$	-	$	-	$	5.3	$	5.3
Notes receivable from Questar		-		-		66.5		66.5		30.3		30.3
Financial liabilities
Checks outstanding in excess of cash balances		-		-		0.1		0.1		-		-
Notes payable to Questar		130.3		130.3		-		-		-		-
Long-term debt, including current portion	$	280.9	$	329.1	$	461.1	$	516.4	$	460.9	$	501.9

Questar Gas

	Carrying		Estimated		Carrying		Estimated		Carrying		Estimated
	Amount		Fair Value		Amount		Fair Value		Amount		Fair Value
	Sept. 30, 2011				Sept. 30, 2010				Dec. 31, 2010
	(in millions)
Financial assets
Cash and cash equivalents	$	-	$	-	$	-	$	-	$	4.7	$	4.7
Financial liabilities
Checks outstanding in excess of cash balances		3.2		3.2		2.2		2.2		-		-
Notes payable to Questar		97.9		97.9		97.0		97.0		153.6		153.6
Long-term debt, including current portion	$	368.0	$	431.7	$	370.0	$	440.3	$	370.0	$	425.3