CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Operating Revenues:
Transportation	$ 242.3	$ 245.0	$ 526.4	$ 532.5
Parking and lending	7.1	7.8	15.0	11.8
Storage	27.4	18.9	55.5	38.7
Other	11.9	4.1	20.3	5.7
Total operating revenues	288.7	275.8	617.2	588.7
Operating Costs and Expenses:
Fuel and transportation	27.4	15.0	50.1	33.7
Operation and maintenance	43.8	41.9	84.0	79.5
Administrative and general	28.9	25.2	60.3	59.4
Depreciation and amortization	67.3	60.7	134.1	124.4
Asset impairment	1.1	2.9	1.2	7.1
Net gain on sale of operating assets	(16.2)	0	(16.2)	(3.6)
Taxes other than income taxes	25.3	21.6	50.9	46.1
Total operating costs and expenses	177.6	167.3	364.4	346.6
Operating income	111.1	108.5	252.8	242.1
Other Deductions (Income):
Interest expense	40.7	41.5	81.2	80.5
Interest expense - affiliates	0	2.0	0	4.0
Interest income	(0.1)	(0.1)	(0.3)	(0.2)
Miscellaneous other income, net	0	(0.1)	(0.2)	(0.2)
Total other deductions	40.6	43.3	80.7	84.1
Income before income taxes	70.5	65.2	172.1	158.0
Income taxes	0.1	0.1	0.3	0.3
Net Income	70.4	65.1	171.8	157.7
Net loss attributable to noncontrolling interests	(0.1)	0	(0.1)	0
Net income attributable to controlling interests	$ 70.5	$ 65.1	$ 171.9	$ 157.7
Basic and diluted net income per unit:
Common units	$ 0.28	$ 0.30	$ 0.70	$ 0.73
Class B units	$ 0.03	$ 0.07	$ 0.21	$ 0.26
Cash distribution declared and paid to common units	$ 0.5325	$ 0.5325	$ 1.065	$ 1.0625
Cash distribution declared and paid to class B units	$ 0.30	$ 0.30	$ 0.60	$ 0.60
Weighted-average number of units outstanding:
Common units	212.3	184.9	210.0	183.8
Class B units	22.9	22.9	22.9	22.9