Debt (Tables)

12 Months Ended

Dec. 31, 2011

Notes to Financial Statements [Abstract]

Schedule of Short-term Debt

The details of short-term debt are as follows:

	December 31,
	2011			2010
	(in millions)
Commercial paper with variable-interest rates	$	219.0		$	242.0
Weighted-average interest rate	0.29		%	0.38		%

Schedule Of Notes Payable

The following table details the notes payable to Questar from Questar Gas and the associated interest rate. There were no notes payable to Questar from Questar Pipeline at December 31, 2011 or 2010.

	December 31,
	2011			2010
	(in millions)
Questar Gas
Notes payable to Questar with variable-interest rates	$	142.7		$	153.6
Interest rate	0.41		%	0.48		%

Schedule of Debt

The details of long-term debt are as follows:

	December 31,
	2011			2010
	(in millions)
Questar Corporation
2.75% Notes due 2016	$	250.0		$	250.0
Questar Pipeline
6.45% and 6.48% Medium-term Notes due 2015 and 2018	30.1			30.1
6.57% and 7.09% Medium-term Notes due 2011	—			180.0
5.83% Notes due 2018	250.0			250.0
4.875% Notes due 2041	180.0			—
Total long-term debt Questar Pipeline	460.1			460.1
Questar Gas
5.00% to 6.91% Medium-term Notes due 2012 to 2018	218.0			218.0
6.89% Medium-term Notes due 2011	—			2.0
6.30% Notes due 2018	50.0			50.0
7.20% Notes due 2038	100.0			100.0
Total long-term debt Questar Gas	368.0			370.0
Total long-term debt outstanding	1,078.1			1,080.1
Less current portion	(91.5		)	(182.0		)
Less unamortized-debt discount	(2.4		)	(0.7		)
Plus unamortized-debt premium	1.0			1.1
Plus fair value hedge adjustment	7.8			—
Total long-term debt	$	993.0		$	898.5

Schedule Of Debt Maturities

The aggregate maturities of Questar Corporation's, Questar Pipeline's and Questar Gas's long-term debt for the next five years are as follows:

	Questar Corporation		Questar Pipeline		Questar Gas		Total
	Years Ending December 31,
	(in millions)
2012	$	—	$	—	$	91.5	$	91.5
2013	—		—		42.0		42.0
2014	—		—		—		—
2015	—		25.1		—		25.1
2016	250.0		—		—		250.0