CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL - USD ($) $ in Millions	Total	Accumulated Other Comp (Loss) Income	General Partner	Common Units Limited Partner
Beginning Balance at Dec. 31, 2014	$ 4,102.3	$ (72.8)	$ 80.0	$ 4,095.1
Add (deduct):
Net income	222.0		4.5	217.5
Distributions paid	(101.5)		(2.0)	(99.5)
Sale of common units, net of related transaction costs	113.1			113.1
Capital contribution from general partner	2.3		2.3
Other comprehensive income (loss), net of tax	(11.5)	(11.5)
Ending Balance at Dec. 31, 2015	4,326.7	(84.3)	84.8	4,326.2
Add (deduct):
Net income	302.2		6.0	296.2
Distributions paid	(102.2)		(2.0)	(100.2)
Other comprehensive income (loss), net of tax	4.2	4.2
Ending Balance at Dec. 31, 2016	4,530.9	(80.1)	88.8	4,522.2
Add (deduct):
Net income	297.0		5.9	291.1
Distributions paid	(102.2)		(2.0)	(100.2)
Other comprehensive income (loss), net of tax	(0.9)	(0.9)
Ending Balance at Dec. 31, 2017	$ 4,724.8	$ (81.0)	$ 92.7	$ 4,713.1