CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current Assets
Cash and cash equivalents	$ 16,000,000	$ 16,800,000
Federal income taxes receivable	4,500,000	10,700,000
Accounts receivable, net	119,300,000	103,600,000
Unbilled gas accounts receivable	93,400,000	78,300,000
Inventories, at lower of average cost or market:
Gas stored underground	40,000,000	39,000,000
Materials and supplies	23,700,000	24,500,000
Current regulatory assets	35,800,000	46,700,000
Prepaid expenses and other	9,500,000	13,100,000
Deferred income taxes - current	9,700,000	13,000,000
Total Current Assets	351,900,000	345,700,000
Property, Plant and Equipment
Distribution property, plant and equipment	2,203,000,000	2,040,900,000
Cost-of-service gas and oil property, plant and equipment, successful efforts method	1,626,400,000	1,397,600,000
Transportation property, plant and equipment	1,774,300,000	1,840,100,000
Other property, plant and equipment	71,000,000	54,700,000
Total Property, Plant and Equipment	5,674,700,000	5,333,300,000
Distribution accumulated depreciation and amortization	(745,200,000)	(716,600,000)
Cost-of-service gas and oil accumulated depreciation, depletion and amortization	(689,800,000)	(617,200,000)
Transportation accumulated depreciation and amortization	(627,200,000)	(629,300,000)
Other accumulated depreciation and amortization	(9,500,000)	(7,000,000)
Total accumulated depreciation, depletion and amortization	(2,071,700,000)	(1,970,100,000)
Net Property, Plant and Equipment	3,603,000,000	3,363,200,000
Investment in unconsolidated affiliate	25,600,000	26,500,000
Other Assets
Goodwill	9,800,000	9,800,000
Noncurrent regulatory assets	20,500,000	21,600,000
Other noncurrent assets	43,500,000	36,500,000
Total Other Assets	73,800,000	67,900,000
TOTAL ASSETS	4,054,300,000	3,803,300,000
Current Liabilities
Short-term debt	276,000,000	263,000,000
Accounts payable and accrued expenses	200,100,000	167,500,000
Production and other taxes	34,700,000	28,000,000
Customer advances	19,800,000	30,200,000
Current regulatory liabilities	14,100,000	5,800,000
Interest payable	10,200,000	9,500,000
Current portion of long-term debt	0	42,000,000
Current portion of capital lease obligation	900,000	700,000
Total Current Liabilities	555,800,000	546,700,000
Long-term debt, less current portion	1,247,100,000	1,098,900,000
Capital lease obligation, less current portion	38,400,000	39,300,000
Deferred income taxes	707,200,000	603,400,000
Asset retirement obligations	67,700,000	67,200,000
Defined benefit pension plan	70,700,000	246,900,000
Other postretirement benefits	42,500,000	56,800,000
Noncurrent regulatory liabilities	61,200,000	54,400,000
Customer contributions in aid of construction	29,100,000	22,900,000
Other noncurrent liabilities	35,800,000	31,200,000
Commitments and contingencies - Note 9
COMMON SHAREHOLDERS' EQUITY
Common stock	464,500,000	442,400,000
Retained earnings	876,100,000	839,500,000
Accumulated other comprehensive loss	(141,800,000)	(246,300,000)
Total Common Shareholders' Equity	1,198,800,000	1,035,600,000
TOTAL LIABILITIES AND COMMON SHAREHOLDERS' EQUITY	4,054,300,000	3,803,300,000
Questar Gas [Member]
Current Assets
Cash and cash equivalents	8,800,000	1,400,000
Federal income taxes receivable	2,800,000	0
Accounts receivable, net	86,100,000	67,000,000
Unbilled gas accounts receivable	93,400,000	78,200,000
Accounts receivable from affiliates	30,400,000	31,800,000
Inventories, at lower of average cost or market:
Gas stored underground	39,200,000	38,300,000
Materials and supplies	12,100,000	13,500,000
Current regulatory assets	30,200,000	41,000,000
Prepaid expenses and other	3,000,000	3,200,000
Deferred income taxes - current	2,900,000	1,500,000
Total Current Assets	308,900,000	275,900,000
Property, Plant and Equipment
Distribution property, plant and equipment	1,839,800,000	1,690,500,000
Other property, plant and equipment	289,800,000	281,600,000
Construction work in progress	73,400,000	68,800,000
Total Property, Plant and Equipment	2,203,000,000	2,040,900,000
Total accumulated depreciation, depletion and amortization	(745,200,000)	(716,600,000)
Net Property, Plant and Equipment	1,457,800,000	1,324,300,000
Other Assets
Goodwill	5,600,000	5,600,000
Noncurrent regulatory assets	16,100,000	16,400,000
Other noncurrent assets	4,000,000	3,100,000
Total Other Assets	25,700,000	25,100,000
TOTAL ASSETS	1,792,400,000	1,625,300,000
Current Liabilities
Notes payable to Questar	17,700,000	166,100,000
Accounts payable and accrued expenses	134,000,000	100,500,000
Accounts payable to affiliates	67,800,000	50,900,000
Customer advances	19,800,000	30,200,000
Current regulatory liabilities	11,100,000	4,300,000
Interest payable	5,200,000	4,500,000
Current portion of long-term debt	0	42,000,000
Total Current Liabilities	255,600,000	398,500,000
Long-term debt, less current portion	534,500,000	384,500,000
Deferred income taxes	340,700,000	301,600,000
Asset retirement obligations	600,000	500,000
Noncurrent regulatory liabilities	53,000,000	46,700,000
Customer contributions in aid of construction	29,100,000	22,900,000
Other noncurrent liabilities	3,200,000	3,500,000
Commitments and contingencies - Note 9
COMMON SHAREHOLDERS' EQUITY
Common stock	23,000,000	23,000,000
Additional paid-in capital	263,900,000	172,500,000
Retained earnings	289,400,000	272,100,000
Total Common Shareholders' Equity	576,300,000	467,600,000
TOTAL LIABILITIES AND COMMON SHAREHOLDERS' EQUITY	1,792,400,000	1,625,300,000
Questar Pipeline [Member]
Current Assets
Cash and cash equivalents	2,700,000	7,100,000
Notes receivable from Questar	29,400,000	38,700,000
Accounts receivable, net	18,500,000	19,100,000
Accounts receivable from affiliates	36,600,000	27,500,000
Inventories, at lower of average cost or market:
Materials and supplies	8,100,000	7,200,000
Current regulatory assets	5,600,000	5,700,000
Prepaid expenses and other	4,400,000	7,700,000
Deferred income taxes - current	1,800,000	1,600,000
Total Current Assets	107,100,000	114,600,000
Property, Plant and Equipment
Transportation property, plant and equipment	1,331,000,000	1,394,700,000
Storage	296,200,000	288,900,000
Processing	24,100,000	25,700,000
General and intangible	82,100,000	81,500,000
Construction work in progress	40,900,000	49,300,000
Total Property, Plant and Equipment	1,774,300,000	1,840,100,000
Total accumulated depreciation, depletion and amortization	(627,200,000)	(629,300,000)
Net Property, Plant and Equipment	1,147,100,000	1,210,800,000
Investment in unconsolidated affiliate	25,600,000	26,500,000
Other Assets
Goodwill	4,200,000	4,200,000
Noncurrent regulatory assets	4,400,000	5,200,000
Noncurrent regulatory and other liabilities	7,700,000	9,000,000
Total Other Assets	11,900,000	13,200,000
TOTAL ASSETS	1,291,700,000	1,365,100,000
Current Liabilities
Accounts payable and accrued expenses	20,600,000	23,600,000
Accounts payable to affiliates	9,400,000	16,900,000
Federal income taxes payable	2,900,000	0
Current regulatory liabilities	3,000,000	1,500,000
Interest payable	2,100,000	2,100,000
Total Current Liabilities	38,000,000	44,100,000
Long-term debt, less current portion	458,900,000	458,900,000
Deferred income taxes	228,600,000	242,500,000
Asset retirement obligations	2,200,000	2,100,000
Noncurrent regulatory liabilities	8,200,000	7,700,000
Other noncurrent liabilities	13,900,000	13,800,000
Commitments and contingencies - Note 9
COMMON SHAREHOLDERS' EQUITY
Common stock	6,600,000	6,600,000
Additional paid-in capital	349,500,000	347,500,000
Retained earnings	219,100,000	274,900,000
Accumulated other comprehensive loss	(22,900,000)	(23,200,000)
Total Common Shareholders' Equity	552,300,000	605,800,000
TOTAL LIABILITIES AND COMMON SHAREHOLDERS' EQUITY	$ 1,291,700,000	$ 1,365,100,000