Consolidated Statement of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Operating revenues—related parties	$ 94.2	$ 62.8	[1]
Operating revenues—third parties	2.0	1.1	[1]
Equity in earnings of affiliates	24.8	6.1	[1]
Other income	0.2	0.1	[1]
Total revenues and other income	121.2	70.1	[1]
Costs and Expenses
Operating and maintenance expenses	22.8	16.0	[1]
Depreciation	13.8	5.1	[1]
General and administrative expenses	8.9	8.2	[1]
Taxes other than income taxes	5.4	1.9	[1]
Interest and debt expense	9.9	5.9	[1]
Total costs and expenses	60.8	37.1	[1]
Income before income taxes	60.4	33.0	[1]
Provision for income taxes	0.2	0.2	[1]
Net Income	60.2	32.8	[1]
Less: Net income attributable to noncontrolling interests	3.0
Less: Net income (loss) attributable to Predecessors	4.9	(2.6)	[1]
Net income attributable to the Partnership	52.3	35.4	[1]
Less: General partner’s interest in net income attributable to the Partnership	15.8	6.4	[1]
Limited partners’ interest in net income attributable to the Partnership	$ 36.5	$ 29.0	[1]
Net Income Attributable to the Partnership Per Limited Partner Unit—Basic and Diluted (dollars)
Cash Distributions Paid Per Limited Partner Unit (dollars)	$ 0.4580	$ 0.3400
Common Units [Member]
Net Income Attributable to the Partnership Per Limited Partner Unit—Basic and Diluted (dollars)
Basic, per unit (dollars)	0.44	0.39
Diluted, per unit (dollars)	$ 0.44	$ 0.39
Average Limited Partner Units Outstanding—Basic and Diluted (thousands)
Basic, units	82,628,424	42,514,707
Diluted, units	82,628,424	42,514,707
Common Units [Member] | Public [Member]
Costs and Expenses
Net income attributable to the Partnership	$ 10.7	$ 8.6
Average Limited Partner Units Outstanding—Basic and Diluted (thousands)
Basic, units	24,139,000	21,047,000
Diluted, units	24,139,000	21,047,000
Common Units [Member] | Non-public [Member] | Phillips 66 [Member]
Costs and Expenses
Net income attributable to the Partnership	$ 25.8	$ 8.0
Average Limited Partner Units Outstanding—Basic and Diluted (thousands)
Basic, units	58,490,000	21,468,000
Diluted, units	58,490,000	21,468,000
Subordinated Units [Member]
Net Income Attributable to the Partnership Per Limited Partner Unit—Basic and Diluted (dollars)
Basic, per unit (dollars)		$ 0.35
Diluted, per unit (dollars)		$ 0.35
Average Limited Partner Units Outstanding—Basic and Diluted (thousands)
Basic, units		35,217,112
Diluted, units		35,217,112
Subordinated Units [Member] | Non-public [Member] | Phillips 66 [Member]
Costs and Expenses
Net income attributable to the Partnership		$ 12.4
Net Income Attributable to the Partnership Per Limited Partner Unit—Basic and Diluted (dollars)
Basic, per unit (dollars)		$ 0.35
Diluted, per unit (dollars)		$ 0.35
Average Limited Partner Units Outstanding—Basic and Diluted (thousands)
Basic, units		35,217,000
Diluted, units		35,217,000

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