CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Revenues:
Transportation	$ 305.9	$ 289.6
Parking and lending	4.1	2.8
Storage	21.0	19.3
Other	14.0	18.0
Total operating revenues	345.0	329.7
Operating Costs and Expenses:
Fuel and transportation	20.3	28.1
Operation and maintenance	43.4	41.3
Administrative and general	34.7	30.6
Depreciation and amortization	79.0	81.6
Asset impairment	0.0	0.1
Taxes other than income taxes	26.0	25.2
Total operating costs and expenses	203.4	206.9
Operating income	141.6	122.8
Other Deductions (Income):
Interest expense	42.6	45.2
Interest income	(0.1)	(0.1)
Miscellaneous other income	(2.1)	(0.2)
Total other deductions	40.4	44.9
Income before income taxes	101.2	77.9
Income taxes	0.2	0.2
Net Income	$ 101.0	$ 77.7
Net Income per Unit:
Net income per common unit (in units)	$ 0.40	$ 0.31
Weighted-average number of common units outstanding (in units)	250.3	244.3
Cash distribution declared and paid to common units (in units)	$ 0.10	$ 0.10