Contingencies (Narrative) (Details) $ in Millions	Mar. 31, 2016 USD ($)
Indemnification
Environmental accruals	$ 1.6
Losses Related To Contributed Assets Subject to a Deductible before Eligibility For Indemnification Under the Omnibus Agreement[Member]
Indemnification
Aggregate deductible before entitled to indemnification by Phillips 66 for failure to obtain certain consents, licenses and permits	0.2
Litigation Matters [Member] | Losses Related To Contributed Assets Subject to a Deductible before Eligibility For Indemnification Under the Omnibus Agreement[Member]
Indemnification
Aggregate deductible	0.2
Environmental Liabilities [Member] | Losses Related To Contributed Assets Subject to a Deductible before Eligibility For Indemnification Under the Omnibus Agreement[Member]
Indemnification
Aggregate deductible	$ 0.1