Condensed Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Revenues:
Natural gas sales	$ 15,095	$ 16,293
Natural gas transportation	362,565	358,168
Natural gas storage	34,889	19,922
Other	1,167	1,483
Total operating revenues	413,716	395,866
Operating Costs and Expenses:
Cost of natural gas sales	15,095	16,293
Cost of natural gas transportation	5,007	6,071
Operation and maintenance	72,713	68,223
Administrative and general	44,116	47,527
Depreciation and amortization	77,478	77,685
Taxes - other than income taxes	16,908	15,401
Other expense, net	15,222	11,491
Total operating costs and expenses	246,539	242,691
Operating Income	167,177	153,175
Other (Income) and Other Expenses:
Interest expense	37,257	38,822
Allowance for equity and borrowed funds used during construction (AFUDC)	(23,030)	(10,273)
Equity in earnings of unconsolidated affiliates	(1,021)	(1,560)
Miscellaneous other (income) expenses, net	(885)	1,468
Total other (income) and other expenses	12,321	28,457
Net Income	154,856	124,718
Other comprehensive income (loss):
Equity interest in unrealized gain (loss) on interest rate hedges (includes $15 for 2017 and $53 for 2016 of accumulated other comprehensive income reclassification for equity interest in realized losses on interest rate hedges)	35	(234)
Comprehensive Income	$ 154,891	$ 124,484