Condensed Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current Assets:
Cash	$ 0	$ 0
Receivables:
Affiliates	941	489
Advances to affiliate	719,960	811,693
Trade and other	138,084	144,315
Transportation and exchange gas receivables	3,294	1,827
Inventories	69,579	55,209
Regulatory assets	90,451	87,059
Other	7,340	13,305
Total current assets	1,029,649	1,113,897
Investments, at cost plus equity in undistributed earnings	40,860	42,403
Property, Plant and Equipment:
Natural gas transmission plant	12,440,120	11,996,454
Less-Accumulated depreciation and amortization	3,741,959	3,687,473
Total property, plant and equipment, net	8,698,161	8,308,981
Other Assets:
Regulatory assets	260,316	264,001
Other	119,495	102,198
Total other assets	379,811	366,199
Total Assets	10,148,481	9,831,480
Payables:
Affiliates	28,391	29,455
Trade and other	309,011	251,872
Transportation and exchange gas payables	1,423	1,571
Accrued liabilities	132,427	197,697
Total current liabilities	471,252	480,595
Long-Term Debt	2,211,069	2,210,754
Other Long-Term Liabilities:
Asset retirement obligations	272,414	248,518
Regulatory liabilities	467,916	449,391
Advances for construction costs	401,416	283,028
Transportation prepayments	11,599	11,837
Other	6,655	6,088
Total other long-term liabilities	1,160,000	998,862
Contingent Liabilities and Commitments (Note 2)
Owner's Equity:
Member's capital	3,788,499	3,678,499
Retained earnings	2,517,616	2,462,760
Accumulated other comprehensive income	45	10
Total owner's equity	6,306,160	6,141,269
Total liabilities and owner's equity	$ 10,148,481	$ 9,831,480