Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Corporate Structure and Control
Parent, total ownership percentage	64.00%
Parent, limited partner ownership percentage	62.00%
Parent, general partner ownership percentage	2.00%
Related Party Transaction [Line Items]
Operating revenues, related party	$ 16,300,000	$ 17,000,000	$ 18,500,000
Purchase Price Allocation
Purchase price allocation, gross	1,500,000,000
Purchase price allocation, property, plant and equipment, estimated useful lIfe	40 years
Purchase price allocation, depreciation	35,000,000
Purchase price allocation, remaining allocation	700,000,000
Schedule of Equity Method Investments [Line Items]
Equity method investment, distributions	11,500,000	14,300,000	6,200,000
Equity method investment, return of capital	1,438,000	11,327,000	1,925,000
Equity method investment, capital contributions	0	5,806,000	14,834,000
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract]
Allowance for funds used during construction, borrowed	5,300,000	6,000,000	4,700,000
Allowance for funds used during construction, equity	13,299,000	13,222,000	10,588,000
Inventory Disclosure [Abstract]
Excess of replacement cost over LIFO cost	1,300,000
Gathering facilities | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	1.35%	0.18%	0.18%
Gathering facilities | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	2.50%	1.66%	1.66%
Storage facilities | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	2.10%	2.10%	2.10%
Storage facilities | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	2.25%	3.70%	3.70%
Onshore transmission facilities | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	2.61%	2.79%	2.79%
Onshore transmission facilities | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	5.00%	5.71%	5.71%
Offshore transmission facilities | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	1.20%	1.01%	1.01%
Offshore transmission facilities | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	1.20%	1.01%	1.01%
Cardinal Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	45.00%
Equity method investment, return of capital		11,300,000
Equity method investment, capital contributions		5,800,000
Pine Needle LNG Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	35.00%
Equity method investment, return of capital	1,400,000
Operation and maintenance
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment	(7,100,000)	(6,800,000)
Taxes-other than income taxes
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment	7,100,000	6,800,000
Total operating costs and expenses
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment	0	0
Operating Income
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment	0	0
Net Income
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment	0	0
Common management [Member]
Related Party Transaction [Line Items]
Operating revenues, related party	$ 130,700,000