For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of securities, mortgage loans, or other financial instruments pledged as collateral for deposits.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Supplemental Financial Information - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		4 Months Ended	5 Months Ended	9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 88.4	$ 33.9		$ 88.4	$ 33.9		$ 11.4
Deposit Liabilities, Collateral Issued, Financial Instruments		31.4			31.4
Letters of credit outstanding, amount		$ 151.1			$ 151.1
Revenue Benchmark [Member] \| Customer Concentration Risk
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		100.00%	100.00%	100.00%	100.00%	100.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk \| Floaters \| US Gulf Of Mexico
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		46.00%	38.00%	64.00%	50.00%	56.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk \| Floaters \| AUSTRALIA
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage	77.00%	64.00%	100.00%		62.00%	91.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk \| Jackups \| US Gulf Of Mexico
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage			11.00%			11.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk \| Jackups \| SAUDI ARABIA
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		56.00%	55.00%	57.00%	57.00%	56.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk \| Jackups \| MEXICO
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage	51.00%	52.00%	74.00%		54.00%	54.00%
Total S.A. \| Revenue Benchmark [Member] \| Customer Concentration Risk
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		14.00%	5.00%	0.00%	9.00%	10.00%
Total S.A. \| Revenue Benchmark [Member] \| Customer Concentration Risk \| Floaters
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage			32.00%			75.00%
British Petroleum \| Revenue Benchmark [Member] \| Customer Concentration Risk
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		9.00%	11.00%	14.00%	9.00%	9.00%
British Petroleum \| Revenue Benchmark [Member] \| Customer Concentration Risk \| Floaters
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		3.00%	14.00%	37.00%	2.00%	23.00%
British Petroleum \| Revenue Benchmark [Member] \| Customer Concentration Risk \| Jackups
Restricted Cash and Cash Equivalents Items [Line Items]
Concentration risk, percentage		24.00%	24.00%	17.00%	24.00%	21.00%