Acquisitions (Details) - U.S. a in Thousands, $ in Millions	3 Months Ended
	Dec. 31, 2019 USD ($) a
Texas Delaware
Business Acquisition [Line Items]
Oil and gas acres, undeveloped, net | a	40
Payments to acquire oil and gas property | $	$ 106
Eagle Ford
Business Acquisition [Line Items]
Oil and gas acres, undeveloped, net | a	18
Payments to acquire oil and gas property | $	$ 191
Working interest percentage acquired	100.00%