Major Customers Major Customers (Sales of Purchased Oil and Gas (Details)	12 Months Ended
Dec. 31, 2020 Rate	Dec. 31, 2019 Rate	Dec. 31, 2018 Rate
Occidental Energy Marketing Inc. \| Sales of Purchased Commodities [Member]
Concentration Risk [Line Items]
Concentration risk percent	28.00%	30.00%	34.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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