Debt (Details) (USD $)								9 Months Ended																																							9 Months Ended									9 Months Ended										9 Months Ended																						9 Months Ended				9 Months Ended		9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Dec. 31, 2010 1.625% Series A Convertible Senior Notes due December 2037 Transocean Ltd. and Subsidiaries	Sep. 30, 2011 1.50% Series B Convertible Senior Notes due December 2037 Transocean Ltd. and Subsidiaries	Dec. 31, 2010 1.50% Series B Convertible Senior Notes due December 2037 Transocean Ltd. and Subsidiaries	Sep. 30, 2011 1.50% Series C Convertible Senior Notes due December 2037 Transocean Ltd. and Subsidiaries	Dec. 31, 2010 1.50% Series C Convertible Senior Notes due December 2037 Transocean Ltd. and Subsidiaries	Sep. 30, 2011 Transocean Ltd. and Subsidiaries	Dec. 31, 2010 Transocean Ltd. and Subsidiaries	Dec. 31, 2010 Transocean Ltd. and Subsidiaries ODL Loan Facility	Sep. 30, 2011 Transocean Ltd. and Subsidiaries Commercial paper program	Dec. 31, 2010 Transocean Ltd. and Subsidiaries Commercial paper program	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.625% Notes due April 2011	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 5% Notes due February 2013	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 5% Notes due February 2013	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 5.25% Senior Notes due March 2013	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 5.25% Senior Notes due March 2013	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 4.95% Senior Notes due November 2015	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 4.95% Senior Notes due November 2015	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 6.00% Senior Notes due March 2018	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.00% Senior Notes due March 2018	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 7.375% Senior Notes due April 2018	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7.375% Senior Notes due April 2018	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 6.50% Senior Notes due November 2020	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.50% Senior Notes due November 2020	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 8% Debentures due April 2027	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 8% Debentures due April 2027	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 7.45% Notes due April 2027	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7.45% Notes due April 2027	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 7% Notes due June 2028	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7% Notes due June 2028	Sep. 30, 2011 Transocean Ltd. and Subsidiaries Capital lease contract due August 2029	Dec. 31, 2010 Transocean Ltd. and Subsidiaries Capital lease contract due August 2029	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 7.5% Notes due April 2031	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7.5% Notes due April 2031	Sep. 30, 2011 Transocean Ltd. and Subsidiaries 6.80% Senior Notes due March 2038	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.80% Senior Notes due March 2038	Sep. 30, 2011 Consolidated variable interest entities	Dec. 31, 2010 Consolidated variable interest entities	Sep. 30, 2011 Consolidated variable interest entities TPDI Credit Facilities due March 2015	Dec. 31, 2010 Consolidated variable interest entities TPDI Credit Facilities due March 2015	Sep. 30, 2011 Consolidated variable interest entities ADDCL Credit Facilities due December 2017	Dec. 31, 2010 Consolidated variable interest entities ADDCL Credit Facilities due December 2017	Sep. 30, 2011 Consolidated variable interest entities TPDI Notes due October 2019	Dec. 31, 2010 Consolidated variable interest entities TPDI Notes due October 2019	Dec. 31, 2010 ODL Loan Facility	Sep. 30, 2011 Commercial paper program	Dec. 31, 2010 Commercial paper program	Sep. 30, 2011 6.625% Notes due April 2011	Apr. 30, 2011 6.625% Notes due April 2011	Dec. 31, 2010 6.625% Notes due April 2011	Sep. 30, 2011 5% Notes due February 2013	Dec. 31, 2010 5% Notes due February 2013	Sep. 30, 2011 5.25% Senior Notes due March 2013	Dec. 31, 2010 5.25% Senior Notes due March 2013	Sep. 30, 2011 TPDI Credit Facilities due March 2015	Dec. 31, 2010 TPDI Credit Facilities due March 2015	Sep. 30, 2011 4.95% Senior Notes due November 2015	Dec. 31, 2010 4.95% Senior Notes due November 2015	Sep. 30, 2011 ADDCL Credit Facilities due December 2017	Dec. 31, 2010 ADDCL Credit Facilities due December 2017	Sep. 30, 2011 6.00% Senior Notes due March 2018	Dec. 31, 2010 6.00% Senior Notes due March 2018	Sep. 30, 2011 7.375% Senior Notes due April 2018	Dec. 31, 2010 7.375% Senior Notes due April 2018	Sep. 30, 2011 TPDI Notes due October 2019	Dec. 31, 2010 TPDI Notes due October 2019	Sep. 30, 2011 6.50% Senior Notes due November 2020	Dec. 31, 2010 6.50% Senior Notes due November 2020	Sep. 30, 2011 8% Debentures due April 2027	Dec. 31, 2010 8% Debentures due April 2027	Sep. 30, 2011 7.45% Notes due April 2027	Dec. 31, 2010 7.45% Notes due April 2027	Sep. 30, 2011 7% Notes due June 2028	Dec. 31, 2010 7% Notes due June 2028	Sep. 30, 2011 Capital lease contract due August 2029	Dec. 31, 2010 Capital lease contract due August 2029	Sep. 30, 2011 7.5% Notes due April 2031	Dec. 31, 2010 7.5% Notes due April 2031	Sep. 30, 2011 1.625% Series A Convertible Senior Notes due December 2037	Dec. 31, 2010 1.625% Series A Convertible Senior Notes due December 2037	Sep. 30, 2011 1.50% Series B Convertible Senior Notes due December 2037	Dec. 31, 2010 1.50% Series B Convertible Senior Notes due December 2037	Sep. 30, 2011 1.50% Series C Convertible Senior Notes due December 2037	Dec. 31, 2010 1.50% Series C Convertible Senior Notes due December 2037	Sep. 30, 2011 6.80% Senior Notes due March 2038	Dec. 31, 2010 6.80% Senior Notes due March 2038	Sep. 30, 2011 Five Year Revolving Credit Facility	Sep. 30, 2011 TPDI Credit Facilities Senior Term Loan Due March 2015	Sep. 30, 2011 TPDI Credit Facilities Junior Term Loan Due March 2015	Sep. 30, 2011 TPDI Credit Facilities Revolving Credit Facility Due March 2015	Sep. 30, 2011 ADDCL Credit Facilities Tranche A Due November 2017	Sep. 30, 2011 ADDCL Credit Facilities Tranche C Due November 2017	Sep. 30, 2011 ADDCL Secondary Loan Facility Due December 2015
Long-term debt by current and noncurrent
Total debt	$ 11,100,000,000	$ 11,221,000,000	$ 11,000,000	$ 1,667,000,000	$ 1,625,000,000	$ 1,648,000,000	$ 1,605,000,000	$ 10,232,000,000	$ 10,271,000,000	$ 10,000,000	$ 146,000,000	$ 88,000,000	$ 167,000,000	$ 254,000,000	$ 255,000,000	$ 510,000,000	$ 511,000,000	$ 1,121,000,000	$ 1,099,000,000	$ 997,000,000	$ 997,000,000	$ 247,000,000	$ 247,000,000	$ 899,000,000	$ 899,000,000	$ 57,000,000	$ 57,000,000	$ 96,000,000	$ 96,000,000	$ 312,000,000	$ 313,000,000	$ 681,000,000	$ 694,000,000	$ 598,000,000	$ 598,000,000	$ 999,000,000	$ 999,000,000	$ 868,000,000	$ 950,000,000	$ 490,000,000	$ 560,000,000	$ 230,000,000	$ 242,000,000	$ 148,000,000	$ 148,000,000	$ 10,000,000	$ 146,000,000	$ 88,000,000			$ 167,000,000	$ 254,000,000	$ 255,000,000	$ 510,000,000	$ 511,000,000	$ 490,000,000	$ 560,000,000	$ 1,121,000,000	$ 1,099,000,000	$ 230,000,000	$ 242,000,000	$ 997,000,000	$ 997,000,000	$ 247,000,000	$ 247,000,000	$ 148,000,000	$ 148,000,000	$ 899,000,000	$ 899,000,000	$ 57,000,000	$ 57,000,000	$ 96,000,000	$ 96,000,000	$ 312,000,000	$ 313,000,000	$ 681,000,000	$ 694,000,000	$ 598,000,000	$ 598,000,000		$ 11,000,000	$ 1,667,000,000	$ 1,625,000,000	$ 1,648,000,000	$ 1,605,000,000	$ 999,000,000	$ 999,000,000
Debt due within one year	1,926,000,000	2,012,000,000	11,000,000	1,667,000,000	1,625,000,000			1,830,000,000	1,917,000,000	10,000,000	146,000,000	88,000,000	167,000,000																			17,000,000	16,000,000					96,000,000	95,000,000	70,000,000	70,000,000	26,000,000	25,000,000			10,000,000	146,000,000	88,000,000			167,000,000					70,000,000	70,000,000			26,000,000	25,000,000															17,000,000	16,000,000				11,000,000	1,667,000,000	1,625,000,000
Long-term debt	9,174,000,000	9,209,000,000						8,402,000,000	8,354,000,000																													772,000,000	855,000,000
Debt instrument interest rate stated percentage (as a percent)																																																	6.625%			5.00%		5.25%				4.95%				6.00%		7.375%				6.50%		8.00%		7.45%		7.00%				7.50%		1.625%		1.50%		1.50%		6.80%
Debt instrument maturity date																																																	April 2011			February 2013		March 2013		March 2015		November 2015		December 2017		March 2018		April 2018		October 2019		November 2020		April 2027		April 2027		June 2028		August 2029		April 2031		December 2037		December 2037		December 2037		March 2038
Percentage ownership interest in Transocean Inc. by Transocean Ltd. (as a percent)								100.00%
Independent assets and operations of Transocean Inc. as a percentage of total consolidated assets and operations of Transocean Ltd. (as a percent)								1.00%
Scheduled maturities of debt
2012	1,938,000,000							1,842,000,000																														96,000,000
2013	2,590,000,000							2,492,000,000																														98,000,000
2014	120,000,000							21,000,000																														99,000,000
2015	334,000,000							23,000,000																														311,000,000
2016	1,186,000,000							1,125,000,000																														61,000,000
Thereafter	4,982,000,000							4,779,000,000																														203,000,000
Total debt, excluding unamortized discounts, premiums and fair value adjustments	11,150,000,000							10,282,000,000																														868,000,000
Total unamortized discounts, premiums and fair value adjustments	(50,000,000)							(50,000,000)
Total debt	11,100,000,000	11,221,000,000	11,000,000	1,667,000,000	1,625,000,000	1,648,000,000	1,605,000,000	10,232,000,000	10,271,000,000	10,000,000	146,000,000	88,000,000	167,000,000	254,000,000	255,000,000	510,000,000	511,000,000	1,121,000,000	1,099,000,000	997,000,000	997,000,000	247,000,000	247,000,000	899,000,000	899,000,000	57,000,000	57,000,000	96,000,000	96,000,000	312,000,000	313,000,000	681,000,000	694,000,000	598,000,000	598,000,000	999,000,000	999,000,000	868,000,000	950,000,000	490,000,000	560,000,000	230,000,000	242,000,000	148,000,000	148,000,000	10,000,000	146,000,000	88,000,000			167,000,000	254,000,000	255,000,000	510,000,000	511,000,000	490,000,000	560,000,000	1,121,000,000	1,099,000,000	230,000,000	242,000,000	997,000,000	997,000,000	247,000,000	247,000,000	148,000,000	148,000,000	899,000,000	899,000,000	57,000,000	57,000,000	96,000,000	96,000,000	312,000,000	313,000,000	681,000,000	694,000,000	598,000,000	598,000,000		11,000,000	1,667,000,000	1,625,000,000	1,648,000,000	1,605,000,000	999,000,000	999,000,000
Credit facility term (in years)																																															5
Credit facility maximum borrowing capacity																																															1,500,000,000									1,265,000,000																																2,000,000,000			75,000,000	215,000,000	399,000,000	90,000,000
Credit facility weighted-average interest rate (as a percent)																																															0.90%
Minimum facility fee on the daily amount of five-year revolving credit facility (as a percent)																																																																																								0.10%
Maximum facility fee on the daily amount of five-year revolving credit facility (as a percent)																																																																																								0.30%
Facility fee on the daily amount of the five-year revolving credit facility (as a percent)																																																																																								0.175%
Letters of credit issued and outstanding																																																																																								41,000,000
Credit facility available borrowing capacity																																																																																								1,900,000,000
Debt instrument face amount																																																		700,000,000																																							1,000,000,000	190,000,000
Aggregate commitment of subsidiary in secured term loan																																																								595,000,000
Credit facility amount outstanding																																																								980,000,000
Debt due to a subsidiary, eliminated in consolidation																																																								490,000,000										148,000,000																												51,000,000
Principal amount outstanding																																																																		$ 296,000,000															$ 11,000,000	$ 1,680,000,000	$ 1,680,000,000	$ 1,722,000,000	$ 1,722,000,000							$ 203,000,000	$ 399,000,000	$ 78,000,000
Weighted-average interest rate (as a percent)																																																								2.00%										2.40%																										1.12%		3.50%
Percentage of total commitment under ADDCL secondary bank credit agreement provided by subsidiary (as a percent)																																																																																														65.00%