Commitments and Contingencies Legal, Environmental or Regulatory (Details)			1 Months Ended		25 Months Ended	53 Months Ended
	Oct. 07, 2019 count	May 16, 2016 employee count	Jul. 31, 2019 USD ($)	May 31, 2015 bbl	May 31, 2018 count	Sep. 30, 2019 USD ($) lawsuit	Apr. 25, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 07, 2018 count
Legal, Environmental or Regulatory Matters
Estimated undiscounted reserve for environmental liabilities						$ 135,000,000		$ 135,000,000
Amounts probable of recovery under insurance and from third parties under indemnification agreements						62,000,000		61,000,000
Trade accounts receivable and other receivables, net
Legal, Environmental or Regulatory Matters
Amounts probable of recovery under insurance and from third parties under indemnification agreements						31,000,000		28,000,000
Other long-term assets, net
Legal, Environmental or Regulatory Matters
Amounts probable of recovery under insurance and from third parties under indemnification agreements						31,000,000		33,000,000
Other current liabilities
Legal, Environmental or Regulatory Matters
Estimated undiscounted reserve for environmental liabilities, short-term						62,000,000		43,000,000
Other long-term liabilities and deferred credits
Legal, Environmental or Regulatory Matters
Estimated undiscounted reserve for environmental liabilities, long-term						73,000,000		$ 92,000,000
Line 901 Incident
Legal, Environmental or Regulatory Matters
Estimated undiscounted reserve for environmental liabilities						79,000,000
Amounts probable of recovery under insurance and from third parties under indemnification agreements						55,000,000
Estimated size of release (in bbl) | bbl				2,934
Estimated size of release to reach Pacific Ocean (in bbl) | bbl				598
Aggregate total estimated costs						380,000,000
Recoveries from insurance carriers						200,000,000
Total release costs probable of recovery						255,000,000
Line 901 Incident | Trade accounts receivable and other receivables, net
Legal, Environmental or Regulatory Matters
Amounts probable of recovery under insurance and from third parties under indemnification agreements						26,000,000
Line 901 Incident | Other current liabilities
Legal, Environmental or Regulatory Matters
Estimated undiscounted reserve for environmental liabilities, short-term						$ 52,000,000
Line 901 Incident | May 2016 Indictment
Legal, Environmental or Regulatory Matters
Number of employees charged | employee		1
Total counts included in the indictment | count		46
Number of felony discharges found guilty | count									1
Number of misdemeanor charges found guilty | count									8
Number of misdemeanor charges found guilty, reporting | count									1
Number of misdemeanor charges found guilty, strict liability discharge | count									1
Number of misdemeanor charges found guilty, strict liability animal takings | count									6
Number of misdemeanor charges found not guilty, strict liability animal takings | count									1
Number of charges jury deadlocked | count									3
Number of charges jury deadlocked, felony discharges | count									2
Number of charges jury deadlocked, strict liability animal takings count | count									1
Number of misdemeanor discharges dropped | count									2
Number of counts dismissed | count					31
Number of felony charges dismissed | count					1
Fines or penalties assessed							$ 3,350,000
Line 901 Incident | Class Action Lawsuits
Legal, Environmental or Regulatory Matters
Number of cases filed during the period | lawsuit						9
Number of cases consolidated into a single proceeding | lawsuit						6
Line 901 Incident | Securities Law Class Action Lawsuits
Legal, Environmental or Regulatory Matters
Number of cases filed during the period | lawsuit						2
Line 901 Incident | Unitholder Derivative Lawsuits
Legal, Environmental or Regulatory Matters
Number of cases filed during the period | lawsuit						4
San Joaquin Valley Air Pollution Control District
Legal, Environmental or Regulatory Matters
Fines or penalties assessed			$ 597,000
Reduced fine paid			$ 275,000
Forecast | Line 901 Incident | May 2016 Indictment
Legal, Environmental or Regulatory Matters
Number of felony charges dismissed | count	2