Pending Felix Acquisition (Details) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) a Well $ / shares shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 0	$ 0	$ 799
Interest Expense		159	$ 163	$ 188
Senior Notes Due Twenty Thirty [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Proceeds from Issuance of Debt	$ 900
Debt instrument stated interest rate	4.50%
Felix [Member]
Business Acquisition [Line Items]
Unadjusted purchase price		2,500
Payments to Acquire Businesses, Gross		$ 900
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares		152,963,671
Unadjusted equity consideration		$ 1,600
Business Acquisition, Share Price | $ / shares		$ 10.46
Interest Expense		$ 3
Business Acquisition, Transaction Costs		$ 3
Gas and Oil Area, Developed, Net | a		58,500
Number of productive benches		6
Gross drillable locations | Well		1,500