CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) In Millions, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Operating Revenues:
Gas transportation	$ 251.8	$ 234.2	$ 786.6	$ 734.0
Parking and lending	2.2	5.5	8.5	23.8
Gas storage	12.0	13.1	37.5	41.5
Other	2.9	4.8	9.3	15.5
Total operating revenues	268.9	257.6	841.9	814.8
Operating Costs and Expenses:
Fuel and gas transportation	26.7	27.7	78.7	81.8
Operation and maintenance	45.9	36.8	123.1	100.2
Administrative and general	31.1	33.2	101.9	98.8
Depreciation and amortization	55.8	54.2	168.9	161.3
Asset impairment	0.1	3.3	28.6	5.8
Net gain on disposal of operating assets	(5.3)	(12.7)	(3.9)	(11.6)
Taxes other than income taxes	22.2	22.0	67.1	66.0
Total operating costs and expenses	176.5	164.5	564.4	502.3
Operating income	92.4	93.1	277.5	312.5
Other Deductions (Income):
Interest expense	37.6	35.3	113.5	106.2
Interest expense - affiliates	2.0	2.0	6.0	6.0
Loss on debt extinguishment	5.8	0	13.2	0
Interest income	(0.1)	(0.2)	(0.3)	(0.5)
Miscellaneous other income, net	(0.2)	0	(0.6)	(0.1)
Total other deductions	45.1	37.1	131.8	111.6
Income before income taxes	47.3	56.0	145.7	200.9
Income taxes	0.1	0.2	0.3	0.4
Net Income	$ 47.2	$ 55.8	$ 145.4	$ 200.5
Basic and diluted net income per unit:
Common units	$ 0.23	$ 0.28	$ 0.72	$ 1.02
Class B units	$ 0	$ 0.07	$ 0.04	$ 0.39
Cash distribution declared and paid to common units	$ 0.525	$ 0.51	$ 1.5675	$ 1.515
Cash distribution declared and paid to class B units	$ 0.30	$ 0.30	$ 0.90	$ 0.90
Weighted-average number of units outstanding:
Common units	175.7	169.7	172.5	169.7
Class B units	22.9	22.9	22.9	22.9