Derivative Instruments (Gains And Losses On Derivatives Designated As Cash Flow Hedges) (Details) - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Derivative [Line Items]
Net change in fair value of derivatives	$ 0	$ (12,900,000)
Foreign Exchange Forward \| Loss on Impairment
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated Other Comprehensive Income ("AOCI") into Income (Effective Portion)	5,600,000
Cash Flow Hedges
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income ("OCI") (Effective Portion)	0	(12,900,000)
Gain (Loss) Reclassified from Accumulated Other Comprehensive Income ("AOCI") into Income (Effective Portion)	(5,600,000)	(100,000)
Net change in fair value of derivatives	0
Cash Flow Hedges \| Foreign Exchange Forward
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income ("OCI") (Effective Portion)		(12,900,000)
Gain (Loss) Reclassified from Accumulated Other Comprehensive Income ("AOCI") into Income (Effective Portion)	$ (5,600,000)	(100,000)
Cash Flow Hedges \| Foreign Exchange Forward \| Contract Drilling
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated Other Comprehensive Income ("AOCI") into Income (Effective Portion)		(900,000)
Cash Flow Hedges \| Foreign Exchange Forward \| Depreciation Expense
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated Other Comprehensive Income ("AOCI") into Income (Effective Portion)		$ 1,000,000.0

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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