Acquisition (Details) - Chevron North Midway-Sunset Acquisition $ / shares in Units, $ in Millions		1 Months Ended
	May 31, 2020 USD ($) day $ / shares	May 31, 2020 USD ($) a
Business Acquisition [Line Items]
Area of land acquired (in acres) | a		740
Consideration transferred in acquisition		$ 5
Payments to acquire business		2
Contingent consideration liability	$ 3	$ 3
Contingent consideration liability triggering event, minimum price (in dollars per share) | $ / shares	$ 45.00
Threshold consecutive days for contingent consideration liability triggering event | day	30