Investments, Loans and Long-Term Receivables (OnCue Holdings, LLC) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
OnCue Holdings LLC
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	50.00%
Maximum loss exposure	$ 148
Equity investments	79
Maximum potential amount of future payments under the guarantees	69
Variable Interest Entity, Primary Beneficiary \| Phillips 66 Partners LP
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 3,136	$ 2,961

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

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