CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (Unaudited) - USD ($) $ in Millions	Total	Accumulated Other Comp (Loss) Income	General Partner	Limited Partner Common Units
Beginning balance at Dec. 31, 2015	$ 4,326.7	$ (84.3)	$ 84.8	$ 4,326.2
Add (deduct):
Net income	166.7		3.3	163.4
Distributions paid	(51.1)		(1.0)	(50.1)
Other comprehensive income, net of tax	2.9	2.9
Ending balance at Jun. 30, 2016	4,445.2	(81.4)	87.1	4,439.5
Beginning balance at Dec. 31, 2016	4,530.9	(80.1)	88.8	4,522.2
Add (deduct):
Net income	143.0		2.9	140.1
Distributions paid	(51.1)		(1.0)	(50.1)
Other comprehensive income, net of tax	0.5	0.5
Ending balance at Jun. 30, 2017	$ 4,623.3	$ (79.6)	$ 90.7	$ 4,612.2