Condensed Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating Revenues:
Natural gas sales	$ 10,717	$ 26,239	$ 20,863	$ 53,281
Natural gas transportation	247,501	238,069	509,968	478,445
Natural gas storage	34,707	35,043	70,457	71,863
Other	839	1,500	2,355	2,618
Total operating revenues	293,764	300,851	603,643	606,207
Operating Costs and Expenses:
Cost of natural gas sales	10,717	26,239	20,863	53,281
Cost of natural gas transportation	7,777	6,982	19,160	18,346
Operation and maintenance	74,135	70,998	135,588	132,477
Administrative and general	42,712	37,885	88,782	78,627
Depreciation and amortization	66,380	66,013	132,375	130,256
Taxes - other than income taxes	12,873	11,863	26,466	25,398
Other (income) expense, net	15,680	3,750	23,461	(6,100)
Total operating costs and expenses	230,274	223,730	446,695	432,285
Operating Income	63,490	77,121	156,948	173,922
Other (Income) and Other Deductions:
Interest expense	23,668	23,873	47,386	47,695
Interest income - affiliates	(8)	(6)	(15)	(16)
Allowance for equity and borrowed funds used during construction (AFUDC)	(5,071)	(4,058)	(8,582)	(9,395)
Equity in earnings of unconsolidated affiliates	(1,732)	(1,095)	(3,268)	(2,413)
Miscellaneous other (income) deductions, net	(2,048)	2,943	(2,037)	901
Total other (income) and other deductions	14,809	21,657	33,484	36,772
Net Income	48,681	55,464	123,464	137,150
Equity interest in unrealized gain (loss) on interest rate hedge	(133)	(271)	(158)	(240)
Comprehensive Income	$ 48,548	$ 55,193	$ 123,306	$ 136,910