Condensed Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current Assets:
Cash	$ 100	$ 164
Receivables:
Affiliates	2,533	5,903
Advances to affiliates	317,797	253,611
Others, less allowance of $0 ($407 in 2011)	108,496	121,589
Transportation and exchange gas receivables	3,892	4,914
Inventories	45,392	35,608
Regulatory assets	36,006	37,877
Other	18,095	12,973
Total current assets	532,311	472,639
Investments, at cost plus equity in undistributed earnings	54,458	56,994
Property, Plant and Equipment:
Natural gas transmission plant	8,376,177	8,089,338
Less-Accumulated depreciation and amortization	2,909,588	2,801,104
Total property, plant and equipment, net	5,466,589	5,288,234
Other Assets:
Regulatory assets	212,080	207,945
Other	48,507	50,471
Total other assets	260,587	258,416
Total assets	6,313,945	6,076,283
Payables:
Affiliates	30,015	16,937
Other	110,278	108,706
Transportation and exchange gas payables	1,753	2,784
Accrued liabilities	130,966	140,390
Current maturities of long-term debt	0	324,321
Total current liabilities	273,012	593,138
Long-Term Debt	1,428,290	1,029,397
Other Long-Term Liabilities:
Asset retirement obligations	260,261	245,365
Regulatory liabilities	223,015	182,848
Other	6,288	6,182
Total other long-term liabilities	489,564	434,395
Contingent liabilities and commitments (Note 2)
Owner's Equity:
Member's capital	1,958,888	1,841,888
Retained earnings	2,164,978	2,177,811
Accumulated other comprehensive loss	(787)	(346)
Total owner's equity	4,123,079	4,019,353
Total liabilities and owner's equity	$ 6,313,945	$ 6,076,283