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Rowan Transaction (Narrative) (Details) $ / shares in Units, € in Millions, $ in Millions			3 Months Ended				12 Months Ended
	Apr. 11, 2019 EUR (€)	Apr. 11, 2019 USD ($) $ / shares	Mar. 31, 2020 EUR (€)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($)	Oct. 23, 2018 $ / shares
Business Acquisition [Line Items]
Business Combination, Bargain Purchase, Adjustment				$ 6.3		$ 0.0
Tax Assessment					$ 42.0
Deferred Tax Liabilities, Net				35.2						$ 99.0
Rowan Companies [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 16.2		10.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		2.1		$ 1.2
Finite-Lived Intangible Assets, Remaining Amortization Period			1 year 9 months 18 days	1 year 9 months 18 days
Amortization of intangible assets				$ 1.3
Unrecognized Tax Benefits, Increase Resulting from Acquisition		$ 50.4
Business Combination, Acquisition Related Costs						$ 5.9
Rowan Companies [Member] \| Class A ordinary shares, U.S.
Business Acquisition [Line Items]
Shares Issued, Price Per Share \| $ / shares		$ 15.88
Share Price \| $ / shares											$ 33.92
Forecast [Member] \| Rowan Companies [Member]
Business Acquisition [Line Items]
Capitalized Contract Cost, Amortization							$ 5.4	$ 3.8
Luxembourg Inland Revenue [Member] \| Rowan Companies [Member]
Business Acquisition [Line Items]
Unrecognized tax benefit, maximum exposure			€ 142.0	156.7					€ 142.0
Tax Assessment \| €	€ 93.0
Deferred Tax Liabilities, Net				$ 102.6