Condensed Consolidated Statement of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating Revenues:
Natural gas sales	$ 18,438	$ 36,013	$ 46,006	$ 60,584
Natural gas transportation	283,979	269,999	584,360	539,576
Natural gas storage	34,665	35,917	71,260	71,507
Other	1,372	950	2,490	2,274
Total operating revenues	338,454	342,879	704,116	673,941
Operating Costs and Expenses:
Cost of natural gas sales	18,438	36,013	46,006	60,584
Cost of natural gas transportation	6,751	8,143	17,954	18,997
Operation and maintenance	63,905	63,260	124,338	123,714
Administrative and general	44,597	44,997	91,731	92,020
Depreciation and amortization	67,702	63,466	137,611	131,159
Taxes - other than income taxes	11,363	10,935	23,645	22,561
Other expense, net	5,955	5,108	13,406	12,188
Total operating costs and expenses	218,711	231,922	454,691	461,223
Operating Income	119,743	110,957	249,425	212,718
Other (Income) and Other Expenses:
Interest expense	21,197	20,746	43,156	41,300
Allowance for equity and borrowed funds used during construction (AFUDC)	(4,391)	(5,520)	(7,373)	(10,350)
Equity in earnings of unconsolidated affiliates	(1,380)	(1,483)	(2,857)	(2,741)
Miscellaneous other (income) expenses, net	(1,172)	(835)	(770)	(2,515)
Total other (income) and other expenses	14,254	12,908	32,156	25,694
Net Income	105,489	98,049	217,269	187,024
Other comprehensive income (loss):
Equity interest in unrealized gain (loss) on interest rate hedges (includes $86 and $82 for the three months ended and $170 and $161 for the six months ended June 30, 2014 and June 30, 2013, respectively, of accumulated other comprehensive income reclassification for realized losses on interest rate hedges)	(41)	404	(3)	506
Comprehensive Income	$ 105,448	$ 98,453	$ 217,266	$ 187,530