CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Revenues:
Transportation	$ 284.1	$ 287.5
Parking and lending	7.9	4.0
Storage	28.1	19.8
Other	8.4	1.6
Total operating revenues	328.5	312.9
Operating Costs and Expenses:
Fuel and gas transportation	22.7	18.7
Operation and maintenance	40.2	37.6
Administrative and general	31.4	34.2
Depreciation and amortization	66.8	63.7
Asset impairment	0.1	4.2
Net gain on sale of operating assets	0	(3.6)
Taxes other than income taxes	25.6	24.5
Total operating costs and expenses	186.8	179.3
Operating income	141.7	133.6
Other Deductions (Income):
Interest expense	40.5	39.0
Interest expense - affiliates	0	2.0
Interest income	(0.2)	(0.1)
Miscellaneous other income, net	(0.2)	(0.1)
Total other deductions	40.1	40.8
Income before income taxes	101.6	92.8
Income taxes	0.2	0.2
Net Income	$ 101.4	$ 92.6
Basic and diluted net income per unit:
Common units	$ 0.42	$ 0.43
Class B units	$ 0.19	$ 0.19
Cash distribution declared and paid to common units	$ 0.5325	$ 0.53
Cash distribution declared and paid to class B units	$ 0.30	$ 0.30
Weighted-average number of units outstanding:
Common units	207.7	182.7
Class B units	22.9	22.9