Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 employee	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%
Entity number of employees	0
Revenue Recognition [Abstract]
Reserve for rate refund, Current	$ 0
Reserve for rate refund, Noncurrent	0
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory debits (credits)	921,000	(494,000)	(1,023,000)
Regulatory assets	58,141,000	60,298,000
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract]
Allowance for funds used during construction, debt	500,000	700,000	700,000
Allowance for funds used during construction, equity	945,000	1,564,000	1,438,000
Allowance for funds used during construction, composite rate	9.00%	9.00%	9.00%
Interest Payments [Abstract]
Cash payments for interest, net of interest capitalized	44,600,000	44,600,000	44,600,000
Levelized depreciation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory debits (credits)	900,000	(500,000)	(1,000,000)
Regulatory assets	33,261,000	33,979,000
Asset retirement obligation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory assets	57,900,000	51,900,000
Negative salvage [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory assets	(51,200,000)	(42,400,000)
Storage Facilities [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	1.60%	1.60%	1.60%
Storage Facilities [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	2.76%	2.76%	2.76%
Transmission Facilities [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	2.80%	2.80%	2.80%
Transmission Facilities [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	6.97%	6.97%	6.97%
Operation and maintenance [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		(2,200,000)	(2,200,000)
General and administrative [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		(500,000)	(500,000)
Taxes other than income [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		2,700,000	2,700,000
Total operating expenses [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		0	0
Operating Income [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		0	0
Net Income [Member]
Prior Period Reclassification Adjustment [Line Items]
Prior period reclassification adjustment		$ 0	$ 0