Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Right-of-use assets	$ 31		$ 31
Difference between undiscounted cash flows for operating leases	4		4
Rental costs	$ 5	$ 7	$ 11	$ 16
Weighted average lease term (in years)	6 years 10 months 24 days		6 years 10 months 24 days
Weighted average discount rate (as a percentage)	5.46%		5.46%
Other Assets
Lessee, Lease, Description [Line Items]
Right-of-use assets	$ 28		$ 28
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Operating Lease, Liability, Current	5		5
Other Liabilities
Lessee, Lease, Description [Line Items]
Operating Lease, Liability, Noncurrent	26		26
Field equipment
Lessee, Lease, Description [Line Items]
Rental costs	4	5	9	12
Buildings
Lessee, Lease, Description [Line Items]
Rental costs	$ 1	$ 2	$ 2	$ 4