Consolidated Statement of Changes in Equity - USD ($) $ in Millions		Total		Sweeny Fractionator Acquisition [Member]	Explorer Pipeline Company, DCP Sand Hills Pipeline LLC, DCP Southern Hills Pipeline LLC [Member]	Net Investment [Member]	Noncontrolling Interest [Member]	General Partner [Member]	General Partner [Member] Sweeny Fractionator Acquisition [Member]	General Partner [Member] Explorer Pipeline Company, DCP Sand Hills Pipeline LLC, DCP Southern Hills Pipeline LLC [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Common Units [Member] Public [Member]	Common Units [Member] Non-public [Member] Phillips 66 [Member]	Common Units [Member] Non-public [Member] Phillips 66 [Member] Sweeny Fractionator Acquisition [Member]	Common Units [Member] Non-public [Member] Phillips 66 [Member] Explorer Pipeline Company, DCP Sand Hills Pipeline LLC, DCP Southern Hills Pipeline LLC [Member]	Subordinated Units [Member] Non-public [Member] Phillips 66 [Member]
Beginning Balance at Dec. 31, 2014		$ 412.8				$ 340.6		$ (517.0)				$ 415.3	$ 57.1			$ 116.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Less: Net income (loss) attributable to Predecessors		(2.6)	[1]			(2.6)
Net contributions from Phillips 66—Predecessors		98.2				98.2
Issuance of common units		383.9										383.9
Deemed net distributions to General Partner associated with acquisitions		(144.9)						(144.9)
Net income attributable to the Partnership		35.4	[1]					6.4				8.6	8.0			12.4
Accumulated other comprehensive income (loss)		(1.5)									$ (1.5)
Quarterly cash distributions to unitholders and General Partner		(29.1)						(3.6)				(6.4)	(7.1)			(12.0)
Other contributions from Phillips 66		2.6						2.6
Ending Balance at Mar. 31, 2015	[1]	$ 754.8				436.2		$ (656.5)			(1.5)	$ 801.4	$ 58.0			$ 117.2
Units at Dec. 31, 2014		76,575,878						1,531,518				18,888,750	20,938,498			35,217,112
Units Outstanding [Roll Forward]
Units issued associated with a public equity offering		5,250,000										5,250,000
Units issued associated with acquisition					1,726,914					139,538					1,587,376
Units at Mar. 31, 2015		83,552,792						1,671,056				24,138,750	22,525,874			35,217,112
Beginning Balance at Dec. 31, 2015		$ 1,214.2	[2]			824.1		$ (650.3)			(1.5)	$ 808.9	$ 233.0			$ 0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Less: Net income (loss) attributable to Predecessors		4.9				4.9
Net contributions from Phillips 66—Predecessors		90.4				90.4
Allocation of net investment to unitholders and noncontrolling interests						$ (919.4)	$ 848.7	1.3					69.4
Net income attributable to the Partnership		52.3						15.8				10.7	25.8
Net income attributable to noncontrolling interest		3.0					3.0
Accumulated other comprehensive income (loss)		0.7									0.7
Quarterly cash distributions to unitholders and General Partner		(51.4)						(13.6)				(11.1)	(26.7)			$ 0.0
Ending Balance at Mar. 31, 2016		$ 1,314.1					$ 851.7	$ (646.8)			$ (0.8)	$ 808.5	$ 301.5
Units at Dec. 31, 2015		84,171,217						1,683,425				24,138,750	58,349,042
Units Outstanding [Roll Forward]
Units issued associated with acquisition				421,248					8,425					412,823
Units at Mar. 31, 2016		84,592,465						1,691,850				24,138,750	58,761,865

[1] Prior-period financial information has been retrospectively adjusted for acquisitions of businesses under common control.

[2] Prior-period financial information has been retrospectively adjusted for acquisitions of businesses under common control.