Condensed Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current Assets:
Cash	$ 231	$ 164
Receivables:
Affiliates	2,674	5,903
Advances to affiliates	285,952	253,611
Others, less allowance of $26 ($407 in 2011)	109,999	121,589
Transportation and exchange gas receivables	3,379	4,914
Inventories	43,913	35,608
Regulatory assets	38,296	37,877
Other	17,221	12,973
Total current assets	501,665	472,639
Investments, at cost plus equity in undistributed earnings	52,615	56,994
Property, Plant and Equipment:
Natural gas transmission plant	8,260,535	8,089,338
Less-Accumulated depreciation and amortization	2,879,105	2,801,104
Total property, plant and equipment, net	5,381,430	5,288,234
Other Assets:
Regulatory assets	205,236	207,945
Other	48,742	50,471
Total other assets	253,978	258,416
Total assets	6,189,688	6,076,283
Payables:
Affiliates	59,367	16,937
Other	110,791	108,706
Transportation and exchange gas payables	1,484	2,784
Accrued liabilities	129,850	140,390
Current maturities of long-term debt	0	324,321
Total current liabilities	301,492	593,138
Long-Term Debt	1,354,357	1,029,397
Other Long-Term Liabilities:
Asset retirement obligations	250,533	245,365
Regulatory liabilities	202,271	182,848
Other	5,634	6,182
Total other long-term liabilities	458,438	434,395
Contingent liabilities and commitments (Note 2)
Owner's Equity:
Member's capital	1,910,888	1,841,888
Retained earnings	2,165,017	2,177,811
Accumulated other comprehensive loss	(504)	(346)
Total owner's equity	4,075,401	4,019,353
Total liabilities and owner's equity	$ 6,189,688	$ 6,076,283