CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (UNAUDITED) - 3 months ended Mar. 31, 2021 - USD ($) $ in Millions	Total	Non-controlling Interests	Common Units Partners' Capital General Public	Subordinated Units Partners' Capital BP Holdco	General Partner
Beginning Balance at Dec. 31, 2020	$ 254.0	$ 132.5	$ 800.5	$ (680.2)	$ 1.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	47.8	5.8	31.3	9.5	1.2
Distributions to unitholders	(37.6)		(18.2)	(18.2)	$ (1.2)
Partners' Capital Account, Exchanges and Conversions				$ (688.9)
Unit-based compensation	0.1		$ 0.1
Distributions to non-controlling interests	(6.4)	$ (6.4)
Ending Balance at Mar. 31, 2021	$ 257.9