Long-Lived Assets (Disposal) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Dispositions
Net cash proceeds from sale of assets	$ 9	$ 24	$ 70
Gain (loss) on the sale of assets	(62)	(84)	(12)
Gain on termination of construction contracts			132
Assets sold, not discontinued operations | Rig sales
Dispositions
Net cash proceeds from sale of assets	4	20	64
Gain (loss) on the sale of assets	$ (57)	$ (61)	$ 4
Gain (loss) on the sale of assets per diluted share	$ (0.09)	$ (0.10)	$ 0.01
Gain (loss) on disposal of assets, tax effect	$ 0	$ 0	$ 0
Assets sold, not discontinued operations | Other property and equipment
Dispositions
Net cash proceeds from sale of assets	5	4	6
Gain (loss) on the sale of assets	$ (5)	$ (23)	$ (16)