Supplemental Financial Information Revenue from External Customers by Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	$ 525.0	$ 430.1
Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	525.0	430.1
US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	94.7	76.0
UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	72.2	53.5
AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	47.7	50.6
Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	179.3	212.9
BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	131.1	37.1
Floaters \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	324.4	214.8
Floaters \| US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	56.8	41.7
Floaters \| UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0
Floaters \| AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	43.0	37.7
Floaters \| Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	93.5	98.3
Floaters \| BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	131.1	37.1
Jackups \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	152.3	169.8
Jackups \| US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	9.4	8.2
Jackups \| UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	72.2	53.5
Jackups \| AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	4.7	12.9
Jackups \| Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	66.0	95.2
Jackups \| BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0
Other \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	48.3	45.5
Other \| US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	28.5	26.1
Other \| UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0
Other \| AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0
Other \| Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	19.8	19.4
Other \| BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	$ 0.0	$ 0.0