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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The excess of replacement or current cost over the stated LIFO (last in first out) inventory value when the LIFO inventory method is utilized.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets.

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Amount capitalized of allowance for funds used during construction.

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Composite depreciation rate for public utility plants in service.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 25, 2015
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	35,000,000us-gaap_AdjustmentForAmortization
Purchase price allocation, remaining allocation	700,000,000us-gaap_FiniteLivedIntangibleAssetsNet
Schedule of Equity Method Investments [Line Items]
Equity method investment, distributions	9,100,000	11,500,000	14,300,000
Equity method investment, return of capital	2,333,000	1,438,000	11,327,000
Equity method investment, capital contributions	0	0	5,806,000
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract]
Allowance for funds used during construction, borrowed	6,300,000	5,300,000	6,000,000
Allowance for funds used during construction, equity	18,701,000	13,299,000	13,222,000
Inventory Disclosure [Abstract]
Excess of replacement cost over LIFO cost	100,000	300,000
Gathering facilities \| Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	1.35%	1.35%	0.18%
Gathering facilities \| Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	2.50%	2.50%	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%	2.25%	3.70%
Onshore transmission facilities \| Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	2.61%	2.61%	2.79%
Onshore transmission facilities \| Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	5.00%	5.00%	5.71%
Offshore transmission facilities \| Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	1.20%	1.20%	1.01%
Offshore transmission facilities \| Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates	1.20%	1.20%	1.01%
Cardinal Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	45.00%	45.00%
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%	35.00%
Property,PlantandEquipmentAdditions,NetofEquityAFUDC [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		(30,500,000)	(32,400,000)
ContributionsandAdvancesforConstructionCosts [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		30,500,000	32,400,000
Common management [Member]
Related Party Transaction [Line Items]
Operating revenues, related party	$ 115,300,000
Subsequent Event [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Parent, total ownership percentage				60.00%
Parent, limited partner ownership percentage				58.00%
Parent, general partner ownership percentage				2.00%