Balance Sheet (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash	$ 0	$ 0
Receivables:
Trade	38,953	42,702
Affiliated companies	2,198	1,321
Advances to affiliate	137,656	45,137
Other	1,757	598
Materials and supplies	10,070	10,106
Exchange gas due from others	2,265	3,869
Prepayments and other	6,234	5,740
Total current assets	199,133	109,473
PROPERTY, PLANT AND EQUIPMENT, at cost	3,371,479	3,319,516
Less-Accumulated depreciation and amortization	1,479,563	1,424,855
Total property, plant and equipment, net	1,891,916	1,894,661
OTHER ASSETS:
Deferred charges	1,017	2,122
Regulatory assets	29,715	34,900
Total other assets	30,732	37,022
Total assets	2,121,781	2,041,156
Payables:
Trade	16,670	11,243
Affiliated companies	4,499	7,293
Accrued liabilities:
Taxes, other than income taxes	16,409	11,435
Interest	11,417	3,501
Exchange gas due to others	2,116	4,169
Exchange gas offset	1,362	1,428
Customer advances	1,498	1,893
Other	11,514	5,224
Long-term debt due within one year	249,805	184,924
Total current liabilities	315,290	231,110
LONG-TERM DEBT	331,799	334,236
OTHER NONCURRENT LIABILITIES:
Asset retirement obligations	66,010	60,762
Regulatory liabilities	37,709	30,717
Other	3,116	7,316
Total other noncurrent liabilities	106,835	98,795
CONTINGENT LIABILITIES AND COMMITMENTS (Note 2)
OWNER'S EQUITY:
Owner's capital	1,073,892	1,073,892
Retained earnings	293,965	303,123
Total owner's equity	1,367,857	1,377,015
Total liabilities and owner's equity	$ 2,121,781	$ 2,041,156