Drilling Fleet (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures	$ 218	$ 259
Construction in Progress
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Construction work in progress, at beginning of period	753	632
Total capital expenditures	218	259
Changes in accrued capital additions	(27)	32
Construction work in progress impaired		(5)
Property and equipment placed into service	(130)	(151)
Construction work in progress, at end of period	814	767
New builds
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures	114	90
Other property and equipment
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures	$ 104	$ 169