v2.4.0.6
Segment Information (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2011
Property, Plant and Equipment [Line Items]  
Number of segments 3
Number of contract drilling rigs 40
Revenues provided by drilling operations in U.S. Gulf of Mexico $ 132.1
Percent of revenues provided by drilling operations in the U.S. Gulf of Mexico 37.00%
Percent of drilling revenues provided by deepwater drilling operations in the U.S. Gulf of Mexico 63.00%
Deepwater [Member] | Minimum [Member]
  
Property, Plant and Equipment [Line Items]  
Rigs drilling capacity 4,500
Midwater [Member] | Maximum [Member]
  
Property, Plant and Equipment [Line Items]  
Rigs drilling capacity 4,499
Jackup [Member] | Maximum [Member]
  
Property, Plant and Equipment [Line Items]  
Rigs drilling capacity 400
Barge Rig [Member] | Other [Member]
  
Property, Plant and Equipment [Line Items]  
Number of contract drilling rigs 1
U.S Gulf Of Mexico [Member] | Semisubmersibles [Member]
  
Property, Plant and Equipment [Line Items]  
Number of contract drilling rigs 3
Singapore [Member] | Jackup [Member] | Rigs Under Construction [Member]
  
Property, Plant and Equipment [Line Items]  
Number of contract drilling rigs 2
Singapore [Member] | Ultra-Deepwater [Member] | Semisubmersibles [Member]
  
Property, Plant and Equipment [Line Items]  
Number of contract drilling rigs 1
Singapore [Member] | Ultra-Deepwater [Member] | Rigs Under Construction [Member]
  
Property, Plant and Equipment [Line Items]  
Number of contract drilling rigs 3
French Guiana [Member] | Ultra-Deepwater [Member] | Semisubmersibles [Member]
  
Property, Plant and Equipment [Line Items]  
Number of contract drilling rigs 1