Condensed Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets:
Cash	$ 0	$ 0
Receivables:
Affiliates	511	1,109
Advances to affiliate	1,249,372	395,247
Trade and other	161,810	170,422
Transportation and exchange gas receivables	2,930	3,205
Inventories	77,913	40,027
Regulatory assets	105,331	97,149
Other	7,769	12,508
Total current assets	1,605,636	719,667
Investments, at cost plus equity in undistributed earnings	26,892	28,505
Property, Plant and Equipment:
Natural gas transmission plant	14,519,157	13,771,183
Less-Accumulated depreciation and amortization	3,919,145	3,859,520
Total property, plant and equipment, net	10,600,012	9,911,663
Other Assets:
Regulatory assets	287,375	276,315
Other	150,983	141,786
Total other assets	438,358	418,101
Total Assets	12,670,898	11,077,936
Payables:
Affiliates	13,924	43,420
Trade and other	414,824	469,153
Transportation and exchange gas payables	2,072	2,121
Accrued liabilities	154,567	173,602
Long-term debt due within one year	251,541	251,430
Total current liabilities	836,928	939,726
Long-Term Debt	3,194,679	2,191,576
Other Long-Term Liabilities:
Asset retirement obligations	384,319	350,280
Regulatory liabilities	1,010,341	990,702
Advances for construction costs	602,569	426,771
Deferred revenue	234,091	236,729
Other	5,326	4,828
Total other long-term liabilities	2,236,646	2,009,310
Contingent Liabilities and Commitments (Note 3)
Members' Equity
Member's capital	4,428,499	4,088,499
Retained earnings	1,973,404	1,848,488
Accumulated other comprehensive income	742	337
Total member's equity	6,402,645	5,937,324
Total liabilities and member's equity	$ 12,670,898	$ 11,077,936