Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net		$ (19.7)	$ (26.3)
Maximum maturity period for all derivatives		18 months
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains on derivatives not designated as hedging instruments		$ (17.3)	(24.8)	$ 3.6
Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(22.2)	0.9	(2.0)
Foreign Currency Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net		(19.7)	(26.3)
Foreign Exchange Forward [Member] | Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[1],[2]	(21.6)	1.3	(1.6)
Foreign Exchange [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate cash flow hedges outstanding		125.7
British pounds		11.1
Australian dollars		7.8
Euros		73.8
Swiss francs		16.6
Mexican Pesos Hedges Outstanding		8.7
Other currencies		7.7
Foreign Exchange [Member] | Cash Flow Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate cash flow hedges outstanding		311.6
British pounds		152.3
Brazilian reais		57.8
Singapore dollars		13.2
Australian dollars		37.9
Euros		34.1
Other currencies		16.3
Contract Drilling [Member] | Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(22.5)	0.4	(2.5)
Depreciation Expense [Member] | Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		$ 0.9	$ 0.9	$ 0.9

[1] Changes in the fair value of cash flow hedges are recorded in AOCI. Amounts recorded in AOCI associated with cash flow hedges are subsequently reclassified into contract drilling, depreciation or interest expense as earnings are affected by the underlying hedged forecasted transaction.

[2] During the year ended December 31, 2015, $22.5 million of losses were reclassified from AOCI into contract drilling expense and $900,000 of gains were reclassified from AOCI into depreciation expense in our consolidated statement of operations. During the year ended December 31, 2014, $400,000 of gains were reclassified from AOCI into contract drilling expense and $900,000 of gains were reclassified from AOCI into depreciation expense in our consolidated statement of operations.