Drilling Fleet (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended	21 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011	Nov. 30, 2007
Drilling Fleet
Construction work in progress, recorded in property and equipment	$ 899	$ 1,500	$ 899
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	336	4,030	4,366
Number of high-specification jackups purchased and under construction		2
Transocean Honor
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	76	97	173
High-Specification Jackup TBN1
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	70	9	79
High-Specification Jackup TBN2
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	70	9	79
Deepwater Champion
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	43	733	776
Initial investment in construction project				109
Discoverer Luanda
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	11	709	720
Costs as a percentage of total expenditures incurred since inception (as a percent)	100.00%		100.00%
High Specification Jackup TBN3
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	10		10
Discoverer India
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	6	744	750
Discoverer Inspiration
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs		679	679
Dhirubhai Deepwater KG2
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs		677	677
Capitalized interest
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	30	273	303
Mobilization costs
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	$ 20	$ 100	$ 120