Supplemental Financial Information Revenue from External Customers by Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	$ 455.1	$ 437.2	$ 1,300.4	$ 1,168.9
Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	455.1	437.2	1,300.4	1,168.9
US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	100.0	95.2	253.3	271.6
UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	71.0	71.4	192.6	200.1
AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	47.0	51.8	148.3	90.9
ANGOLA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	62.8	23.2	160.1	52.3
Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	127.9	162.2	428.7	478.5
BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	46.4	33.4	117.4	75.5
Floaters \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	243.3	201.7	685.5	489.5
Floaters \| US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	65.3	62.8	152.3	179.3
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	0.0	0.0
Floaters \| AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	40.2	40.2	118.0	72.7
Floaters \| ANGOLA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	62.8	23.2	160.1	52.3
Floaters \| Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	28.6	106.2	137.7	325.1
Floaters \| BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	46.4	0.0	117.4	0.0
Jackups \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	165.9	195.9	480.3	562.4
Jackups \| US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	8.5	6.7	22.5	19.0
Jackups \| UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	71.0	71.4	192.6	200.1
Jackups \| AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	6.8	11.6	30.3	18.2
Jackups \| ANGOLA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0	0.0	0.0
Jackups \| Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	79.6	42.1	234.9	109.7
Jackups \| BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	33.4	0.0	75.5
Managed Rigs \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	45.9	39.6	134.6	117.0
Managed Rigs \| US Gulf Of Mexico \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	26.2	25.7	78.5	73.3
Managed Rigs \| UNITED KINGDOM \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0	0.0	0.0
Managed Rigs \| AUSTRALIA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0	0.0	0.0
Managed Rigs \| ANGOLA \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	0.0	0.0	0.0	0.0
Managed Rigs \| Other Geographic Areas \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	19.7	13.9	56.1	43.7
Managed Rigs \| BRAZIL \| Revenue Benchmark [Member] \| Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
OPERATING REVENUES	$ 0.0	$ 0.0	$ 0.0	$ 0.0