Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Revenues:
Natural gas sales	$ 113,488	$ 65,120	$ 108,359
Natural gas transportation	1,094,807	1,022,990	983,554
Natural gas storage	143,047	140,390	142,556
Other	4,990	5,601	8,045
Total operating revenues	1,356,332	1,234,101	1,242,514
Operating Costs and Expenses:
Cost of natural gas sales	113,488	65,120	108,359
Cost of natural gas transportation	24,936	31,815	35,674
Operation and maintenance	264,631	299,734	281,496
Administrative and general	182,352	174,610	148,113
Depreciation and amortization	265,273	266,445	259,660
Taxes - other than income taxes	43,898	45,086	41,673
Other expense, net	32,606	21,230	12,988
Total operating costs and expenses	927,184	904,040	887,963
Operating Income	429,148	330,061	354,551
Other (Income) and Other Expenses:
Interest expense - affiliate	190	309	262
Interest expense - other	84,000	88,766	94,920
Interest income - affiliate	(45)	(35)	(29)
Interest income - other	(2,068)	(2,351)	(2,119)
Allowance for equity and borrowed funds used during construction (AFUDC)	(18,595)	(19,257)	(15,339)
Equity in earnings of unconsolidated affiliates	(5,678)	(7,458)	(5,164)
Miscellaneous other (income) expenses, net	(2,682)	(2,379)	2,362
Total other (income) and other expenses	55,122	57,595	74,893
Net Income	374,026	272,466	279,658
Other comprehensive income (loss):
Equity interest in unrealized gain (loss) on interest rate hedges (includes $330, $220, and $170 for the years ended December 31, 2013, 2012, and 2011, respectively, of accumulated other comprehensive income reclassification for realized losses on interest rate hedges)	464	(376)	(519)
Comprehensive Income	$ 374,490	$ 272,090	$ 279,139