Long-Lived Assets (Disposal) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Dispositions
Net cash proceeds from sale of assets	$ 7.0	$ 9.0	$ 24.0
Gain (loss) on the sale of assets	(10.0)	(62.0)	(84.0)
Assets sold, not discontinued operations | Rig sales
Dispositions
Net cash proceeds from sale of assets		4.0	20.0
Gain (loss) on the sale of assets		$ (57.0)	$ (61.0)
Gain (loss) on the sale of assets per diluted share		$ (0.09)	$ (0.10)
Gain (loss) on disposal of assets, tax effect		$ 0.0
Assets sold, not discontinued operations | Other property and equipment
Dispositions
Net cash proceeds from sale of assets	7.0	5.0	$ 4.0
Gain (loss) on the sale of assets	$ (10.0)	$ (5.0)	$ (23.0)