v2.4.0.8
Drilling Fleet (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2013
drillingunit
Jun. 30, 2012
Jun. 30, 2013
drillingunit
Jun. 30, 2012
Capital expenditures and other capital additions, including capitalized interest costs        
Construction work in progress, at beginning of period     $ 1,972 $ 1,360
Total capital expenditures 352 207 840 445
Changes in accrued capital expenditures     (29) 18
Construction work in progress, at end of period 1,803 1,257 1,803 1,257
Number of Ultra-Deepwater drillships under construction 4   4  
Ultra-Deepwater Floater TBN1
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     84  
Ultra-Deepwater Floater TBN2
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     82  
Ultra-Deepwater Floater TBN3
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     4  
Ultra-Deepwater Floater TBN4
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     3  
Transocean Ao Thai
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     13 45
Deepwater Asgard
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     24 21
Deepwater Invictus
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     25 13
Transocean Siam Driller
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     74 26
Property and equipment placed into service     (236)  
Transocean Andaman
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     82 26
Property and equipment placed into service     (242)  
Transocean Honor
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures       35
Property and equipment placed into service       (262)
Ownership interest in affiliate (as a percent) 70.00%   70.00%  
Costs as a percentage of total expenditures incurred since inception 100.00%   100.00%  
Other construction projects and capital additions
        
Capital expenditures and other capital additions, including capitalized interest costs        
Total capital expenditures     449 279
Other property and equipment
        
Capital expenditures and other capital additions, including capitalized interest costs        
Property and equipment placed into service     $ (502) $ (304)
Deepwater Asgard and Deepwater Invictus
        
Capital expenditures and other capital additions, including capitalized interest costs        
Number of Ultra-Deepwater Floaters under construction which are expected to commence operations in the first and third quarter of 2014 2   2  
Transocean Siam Driller and Transocean Andaman
        
Capital expenditures and other capital additions, including capitalized interest costs        
Number of high-specification jackups that commenced operations during the period 2   2