Balance Sheet (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
CURRENT ASSETS:
Cash	$ 100	$ 117
Receivables:
Trade	37,964	39,836
Affiliated companies	2,253	1,683
Advances to affiliate	112,195	29,322
Other	7,977	6,700
Materials and supplies, less reserves of $28 at June 30, 2013 and $81 at December 31, 2012	10,320	10,137
Exchange gas due from others	3,456	3,426
Exchange gas offset	1,069	1,277
Prepayments and other	4,343	3,353
Total current assets	179,677	95,851
PROPERTY, PLANT AND EQUIPMENT, at cost	3,173,360	3,163,489
Less-Accumulated depreciation	1,190,852	1,159,944
Total property, plant and equipment, net	1,982,508	2,003,545
OTHER ASSETS:
Deferred charges	7,474	7,918
Regulatory assets	58,645	60,298
Total other assets	66,119	68,216
Total assets	2,228,304	2,167,612
Payables:
Trade	19,076	18,383
Affiliated companies	10,163	10,912
Accrued liabilities:
Taxes, other than income taxes	12,354	10,961
Interest	4,045	4,045
Exchange gas due to others	2,925	6,572
Other	5,044	4,467
Total current liabilities	53,607	55,340
LONG-TERM DEBT	694,125	694,027
OTHER NONCURRENT LIABILITIES:
Asset retirement obligations	69,502	67,557
Other	24,200	22,450
Total other noncurrent liabilities	93,702	90,007
CONTINGENT LIABILITIES AND COMMITMENTS (Note 2)
OWNER'S EQUITY:
Owner's capital	1,060,592	1,060,592
Retained earnings	326,095	267,432
Accumulated other comprehensive income	183	214
Total owner's equity	1,386,870	1,328,238
Total liabilities and owner's equity	$ 2,228,304	$ 2,167,612