Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current Assets:
Cash	$ 113	$ 185
Receivables:
Trade	137,808	116,847
Affiliates	2,601	2,656
Advances to affiliate	526,380	312,165
Other	10,364	8,928
Transportation and exchange gas receivables	6,757	2,876
Inventories:
Gas in storage, at original cost	790	812
Gas in storage, LIFO	1,056	0
Gas available for customer nomination, at average cost	8,553	8,600
Material and supplies, at lower of average cost or market	37,133	36,506
Regulatory assets	37,520	36,706
Other	13,451	14,342
Total current assets	782,526	540,623
Investments, at cost plus equity in undistributed earnings	50,262	55,603
Property, Plant and Equipment:
Natural gas transmission plant	8,867,626	8,506,189
Less-Accumulated depreciation and amortization	3,090,234	2,954,276
Total property, plant and equipment, net	5,777,392	5,551,913
Other Assets:
Regulatory assets	256,612	214,912
Other	57,785	47,764
Total other assets	314,397	262,676
Total assets	6,924,577	6,410,815
Payables:
Trade	106,096	107,795
Affiliates	28,268	32,006
Cash overdrafts	8,539	11,512
Transportation and exchange gas payables	3,599	3,513
Reserve for rate refunds	98,217	0
Accrued liabilities:
Property and other taxes	14,180	13,326
Interest	19,894	20,784
Regulatory liabilities	18,014	14,624
Customer advances	17,811	11,020
Asset retirement obligations	35,902	43,472
Other	47,462	36,107
Total current liabilities	397,982	294,159
Long-Term Debt	1,428,355	1,428,323
Other Long-Term Liabilities:
Asset retirement obligations	238,085	253,398
Regulatory liabilities	269,563	232,888
Other	5,307	5,339
Total other long-term liabilities	512,955	491,625
Contingent Liabilities and Commitments (Note 2)
Owner's Equity:
Member's capital	2,257,499	1,993,412
Retained earnings	2,328,044	2,204,018
Accumulated other comprehensive income (loss)	(258)	(722)
Total owner's equity	4,585,285	4,196,708
Total liabilities and owner's equity	$ 6,924,577	$ 6,410,815