Segment Disclosures and Related Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2019 refinery
Midstream | DCP Midstream
Segment Disclosures And Related Information (Textual) [Abstract]
Percentage of ownership interest	50.00%
Chemicals | CP Chem
Segment Disclosures And Related Information (Textual) [Abstract]
Percentage of ownership interest	50.00%
Refining | Mainly United States And Europe
Segment Disclosures And Related Information (Textual) [Abstract]
Number of refineries	13