CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues:
Transportation	$ 278.7	$ 269.8	$ 597.3	$ 575.7
Parking and lending	7.9	4.4	13.3	8.5
Storage	19.9	23.6	43.3	44.6
Other	11.1	8.5	30.7	22.5
Total operating revenues	317.6	306.3	684.6	651.3
Operating Costs and Expenses:
Fuel and transportation	14.5	11.6	33.7	31.9
Operation and maintenance	51.6	48.3	92.0	91.7
Administrative and general	34.2	35.5	68.8	70.2
Depreciation and amortization	80.2	79.1	160.8	158.1
Loss on sale of assets and impairments	47.1	0.0	47.1	0.0
Taxes other than income taxes	22.8	22.5	50.2	48.5
Total operating costs and expenses	250.4	197.0	452.6	400.4
Operating income	67.2	109.3	232.0	250.9
Other Deductions (Income):
Interest expense	43.9	45.4	90.1	88.0
Interest income	(0.2)	(0.1)	(0.3)	(0.2)
Miscellaneous other income, net	(0.6)	(1.9)	(1.4)	(4.0)
Total other deductions	43.1	43.4	88.4	83.8
Income before income taxes	24.1	65.9	143.6	167.1
Income taxes	0.4	0.2	0.6	0.4
Net income	$ 23.7	$ 65.7	$ 143.0	$ 166.7
Net Income per Unit:
Net income per common unit (in dollars per unit)	$ 0.09	$ 0.26	$ 0.56	$ 0.65
Weighted-average number of common units outstanding (in units)	250.3	250.3	250.3	250.3
Cash distribution declared and paid to common units per common unit (in dollars per unit)	$ 0.10	$ 0.10	$ 0.20	$ 0.20