v2.3.0.15

Segment Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2011 | Sep. 30, 2011
Segment Reporting Information [Line Items] |  |
Number of drillships |  | 7
Revenues provided by drilling operations in U.S. Gulf of Mexico | $ 251.3 | $ 539.4
Percent of revenues provided by drilling operations in the U.S. Gulf of Mexico | 27.00% | 29.00%
Percent of drilling revenues provided by deepwater drilling operations in the U.S. Gulf of Mexico | 74.00% | 68.00%
Minimum [Member] | Deepwater [Member] |  |
Segment Reporting Information [Line Items] |  |
Rigs drilling capacity |  | 4,500
Maximum [Member] | Midwater [Member] |  |
Segment Reporting Information [Line Items] |  |
Rigs drilling capacity |  | 4,499
Maximum [Member] | Jackup [Member] |  |
Segment Reporting Information [Line Items] |  |
Rigs drilling capacity |  | 400
Deepwater [Member] | Other [Member] |  |
Segment Reporting Information [Line Items] |  |
Number of contract drilling rigs |  | 2
Jackup [Member] |  |
Segment Reporting Information [Line Items] |  |
Number of contract drilling rigs |  | 48
Other [Member] | Barge Rig [Member] |  |
Segment Reporting Information [Line Items] |  |
Number of contract drilling rigs |  | 1
Semisubmersibles [Member] |  |
Segment Reporting Information [Line Items] |  |
Number of contract drilling rigs |  | 20

X
- Definition Number Of Contract Drilling Rig + Details
Name: | esv_NumberOfContractDrillingRigs
Namespace Prefix: | esv
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of drillships. + Details
Name: | esv_NumberOfDrillships
Namespace Prefix: | esv
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent Of Drilling Revenues Provided By Deepwater Drilling Operations In The US Gulf Of Mexico + Details
Name: | esv_PercentOfDrillingRevenuesProvidedByDeepwaterDrillingOperationsInUsGulfOfMexico
Namespace Prefix: | esv
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent Of Revenues Provided By Drilling Operations In The US Gulf Of Mexico + Details
Name: | esv_PercentOfRevenuesProvidedByDrillingOperationsInUsGulfOfMexico
Namespace Prefix: | esv
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenues Provided By Drilling Operation + Details
Name: | esv_RevenuesProvidedByDrillingOperation
Namespace Prefix: | esv
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Rigs drilling capacity, feet. + Details
Name: | esv_RigsDrillingCapacityFeet
Namespace Prefix: | esv
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration