Goodwill and Other Intangible Assets and Liabilities (Details) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 29, 2016 $ / shares	Dec. 31, 2015 USD ($) $ / shares $ / bbl	Sep. 30, 2015 $ / shares	Dec. 31, 2015 USD ($) $ / shares $ / bbl	Dec. 31, 2014 USD ($) $ / shares $ / bbl	Jan. 31, 2016 $ / bbl	Jun. 30, 2015 $ / shares	Dec. 02, 2014 $ / shares	Sep. 30, 2014 $ / bbl	Dec. 31, 2013 USD ($)
Goodwill [Line Items]
Finite-Lived Intangible Assets, Expense (Income), Net, Next Twelve Months		$ (8.3)		$ (8.3)
Asset Impairment Charges, Assumptions Used, Weighted Average Capital Cost				11.50%
Price Per Barrel | $ / bbl		35		35	55				95
Goodwill		$ 0.0		$ 0.0	$ 276.1
Drilling contract intangible assets, Gross Carrying Amount		209.0		209.0	209.0					$ 209.0
Intangible Assets, Accumulated Amortization [Roll Forward]
Balance, beginning of period				(163.3)	(130.6)
Amortization				(41.4)	(32.7)
Balance, end of period		(204.7)		(204.7)	(163.3)
Intangible Assets, Net Carrying Amount [Roll Forward]
Balance, beginning of period				45.7	78.4
Amortization				(41.4)	(32.7)
Balance, end of period		4.3		4.3	45.7
Drilling contract intangible liabilities, Gross Carrying Amount		278.0		278.0	278.0					278.0
Intangible Liabilities, Accumulated Amortization [Roll Forward]
Balance, beginning of period				(237.3)	(208.9)
Amortization				(28.1)	(28.4)
Balance, end of period		(265.4)		(265.4)	(237.3)
Intangible Liabilities, Net Carrying Amount [Roll Forward]
Balance, beginning of period				40.7	69.1
Amortization				(28.1)	(28.4)
Balance, end of period		12.6		12.6	40.7
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Total		$ 8.3		$ 8.3
Share Price | $ / shares								$ 25.88
Average Share Price | $ / shares		$ 16.34	$ 17.21
Asset Impairment Charges, Assumptions Used, Terminal Growth Rate				3.00%
Floaters [Member]
Goodwill [Line Items]
Goodwill, Gross		$ 3,081.4		$ 3,081.4	3,081.4					3,081.4
Goodwill		0.0		0.0	83.5					3,081.4
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Goodwill, Impaired, Accumulated Impairment Loss		(3,081.4)		(3,081.4)	(2,997.9)					0.0
Goodwill, Impairment Loss				(83.5)	(2,997.9)
Jackups [Member]
Goodwill [Line Items]
Goodwill, Gross		192.6		192.6	192.6					192.6
Goodwill		0.0		0.0	192.6					192.6
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Goodwill, Impaired, Accumulated Impairment Loss		$ (192.6)		(192.6)	$ 0.0					$ 0.0
Goodwill, Impairment Loss				$ (192.6)
Minimum [Member]
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Share Price During The Period | $ / shares				$ 13.26	$ 25.88
Maximum [Member]
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Share Price During The Period | $ / shares				$ 22.21	41.99
Weighted Average [Member]
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Share Price | $ / shares					$ 35.23		$ 25.31
Scenario, Forecast [Member]
Goodwill [Line Items]
Price Per Barrel | $ / bbl						26
Finite-Lived Intangible Assets, Net, Amortization Income (Expense), Fiscal Year Maturity [Abstract]
Share Price During The Period | $ / shares	$ 8.00