Debt (Details)	1 Months Ended														3 Months Ended	9 Months Ended				9 Months Ended			9 Months Ended																	9 Months Ended											1 Months Ended									9 Months Ended																																														9 Months Ended
	May 31, 2012 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2012 NOK	Dec. 31, 2011 USD ($)	Sep. 30, 2012 5% Notes due February 2013 USD ($)	Dec. 31, 2011 5% Notes due February 2013 USD ($)	Sep. 30, 2012 5.25% Senior Notes due March 2013 USD ($)	Dec. 31, 2011 5.25% Senior Notes due March 2013 USD ($)	Sep. 30, 2012 TPDI Credit Facilities due March 2015 USD ($)	Dec. 31, 2011 TPDI Credit Facilities due March 2015 USD ($)	Sep. 30, 2012 4.95% Senior Notes due November 2015 USD ($)	Dec. 31, 2011 4.95% Senior Notes due November 2015 USD ($)	Dec. 31, 2011 Aker Revolving Credit and Term Loan Facility due December 2015 USD ($)	Feb. 21, 2011 Aker Revolving Credit and Term Loan Facility due December 2015 USD ($)	Sep. 30, 2012 Aker Term Loan Facility due December 2015 USD ($)	Sep. 30, 2012 Aker Term Loan Facility due December 2015 USD ($)	Feb. 21, 2011 Aker Term Loan Facility due December 2015 USD ($)	Sep. 30, 2012 5.05% Senior Notes due December 2016 USD ($)	Dec. 31, 2011 5.05% Senior Notes due December 2016 USD ($)	Sep. 30, 2012 2.5% Senior Notes due October 2017 USD ($)	Sep. 30, 2012 Callable Bonds due February 2016 USD ($)	Dec. 31, 2011 Callable Bonds due February 2016 USD ($)	Sep. 30, 2012 FRN Callable Bonds USD ($)	Sep. 30, 2012 FRN Callable Bonds NOK	Sep. 30, 2012 11% Callable Bonds USD ($)	Sep. 30, 2012 11% Callable Bonds NOK	Sep. 30, 2012 ADDCL Credit Facilities due December 2017 USD ($)	Dec. 31, 2011 ADDCL Credit Facilities due December 2017 USD ($)	Sep. 30, 2012 Eksportfinans Loans due January 2018 USD ($)	Dec. 31, 2011 Eksportfinans Loans due January 2018 USD ($)	Sep. 30, 2012 6.00% Senior Notes due March 2018 USD ($)	Dec. 31, 2011 6.00% Senior Notes due March 2018 USD ($)	Sep. 30, 2012 7.375% Senior Notes due April 2018 USD ($)	Dec. 31, 2011 7.375% Senior Notes due April 2018 USD ($)	Dec. 31, 2011 TPDI Notes due October 2019 USD ($)	Sep. 30, 2012 6.50% Senior Notes due November 2020 USD ($)	Dec. 31, 2011 6.50% Senior Notes due November 2020 USD ($)	Sep. 30, 2012 6.375% Senior Notes due December 2021 USD ($)	Dec. 31, 2011 6.375% Senior Notes due December 2021 USD ($)	Sep. 30, 2012 3.8% Senior Notes due October 2022 USD ($)	Sep. 30, 2012 7.45% Notes due April 2027 USD ($)	Dec. 31, 2011 7.45% Notes due April 2027 USD ($)	Sep. 30, 2012 8% Debentures due April 2027 USD ($)	Dec. 31, 2011 8% Debentures due April 2027 USD ($)	Sep. 30, 2012 7% Notes due June 2028 USD ($)	Dec. 31, 2011 7% Notes due June 2028 USD ($)	Sep. 30, 2012 Capital lease contract due August 2029 USD ($)	Dec. 31, 2011 Capital lease contract due August 2029 USD ($)	Sep. 30, 2012 7.5% Notes due April 2031 USD ($)	Dec. 31, 2011 7.5% Notes due April 2031 USD ($)	Feb. 29, 2012 1.50% Series B Convertible Senior Notes due December 2037 USD ($)	Sep. 30, 2012 1.50% Series B Convertible Senior Notes due December 2037	Dec. 31, 2011 1.50% Series B Convertible Senior Notes due December 2037 USD ($)	Sep. 30, 2012 1.50% Series C Convertible Senior Notes due December 2037 USD ($)	Dec. 31, 2011 1.50% Series C Convertible Senior Notes due December 2037 USD ($)	Sep. 30, 2012 6.80% Senior Notes due March 2038 USD ($)	Dec. 31, 2011 6.80% Senior Notes due March 2038 USD ($)	Sep. 30, 2012 7.35% Senior Notes due December 2041 USD ($)	Dec. 31, 2011 7.35% Senior Notes due December 2041 USD ($)	Sep. 30, 2012 Five Year Revolving Credit Facility USD ($)	Sep. 30, 2012 Five Year Revolving Credit Facility Minimum Facility Fee	Sep. 30, 2012 Five Year Revolving Credit Facility Maximum Facility Fee	Sep. 30, 2012 Transocean Ltd. and Subsidiaries USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 5% Notes due February 2013 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 5% Notes due February 2013 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 5.25% Senior Notes due March 2013 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 5.25% Senior Notes due March 2013 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries TPDI Credit Facilities due March 2015 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 4.95% Senior Notes due November 2015 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 4.95% Senior Notes due November 2015 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries Aker Revolving Credit and Term Loan Facility due December 2015 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 5.05% Senior Notes due December 2016 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 5.05% Senior Notes due December 2016 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 2.5% Senior Notes due October 2017 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries Callable Bonds due February 2016 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries Callable Bonds due February 2016 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries Eksportfinans Loans due January 2018 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries Eksportfinans Loans due January 2018 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 6.00% Senior Notes due March 2018 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 6.00% Senior Notes due March 2018 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 7.375% Senior Notes due April 2018 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 7.375% Senior Notes due April 2018 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 6.50% Senior Notes due November 2020 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 6.50% Senior Notes due November 2020 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 6.375% Senior Notes due December 2021 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 6.375% Senior Notes due December 2021 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 3.8% Senior Notes due October 2022 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 7.45% Notes due April 2027 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 7.45% Notes due April 2027 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 8% Debentures due April 2027 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 8% Debentures due April 2027 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 7% Notes due June 2028 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 7% Notes due June 2028 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries Capital lease contract due August 2029 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries Capital lease contract due August 2029 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 7.5% Notes due April 2031 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 7.5% Notes due April 2031 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 1.50% Series B Convertible Senior Notes due December 2037 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 1.50% Series C Convertible Senior Notes due December 2037 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 1.50% Series C Convertible Senior Notes due December 2037 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 6.80% Senior Notes due March 2038 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 6.80% Senior Notes due March 2038 USD ($)	Sep. 30, 2012 Transocean Ltd. and Subsidiaries 7.35% Senior Notes due December 2041 USD ($)	Dec. 31, 2011 Transocean Ltd. and Subsidiaries 7.35% Senior Notes due December 2041 USD ($)	Sep. 30, 2012 Transocean Inc.	Sep. 30, 2012 Consolidated variable interest entities USD ($)	Dec. 31, 2011 Consolidated variable interest entities USD ($)	Dec. 31, 2011 Consolidated variable interest entities TPDI Credit Facilities due March 2015 USD ($)	Sep. 30, 2012 Consolidated variable interest entities ADDCL Credit Facilities due December 2017 USD ($)	Dec. 31, 2011 Consolidated variable interest entities ADDCL Credit Facilities due December 2017 USD ($)	Dec. 31, 2011 Consolidated variable interest entities TPDI Notes due October 2019 USD ($)	Sep. 30, 2012 TPDI TPDI Credit Facilities due March 2015 USD ($)	Dec. 31, 2011 TPDI TPDI Credit Facilities due March 2015 USD ($)	Sep. 30, 2012 TPDI TPDI Credit Facilities Senior Term Loan Due March 2015 USD ($)	Sep. 30, 2012 TPDI TPDI Credit Facilities Junior Term Loan Due March 2015 USD ($)	Sep. 30, 2012 TPDI TPDI Credit Facilities Revolving Credit Facility Due March 2015 USD ($)	Sep. 30, 2012 TPDI Uncommitted Credit Facility Established by Subsidiary USD ($)	Sep. 30, 2012 ADDCL ADDCL Credit Facilities Tranche A Due November 2017 USD ($)	Sep. 30, 2012 ADDCL ADDCL Credit Facilities Tranche C Due November 2017 USD ($)	Sep. 30, 2012 ADDCL ADDCL Secondary Loan Facility Due December 2015 USD ($)	Dec. 31, 2011 ADDCL ADDCL Secondary Loan Facility Due December 2015 USD ($)
Long-term debt by current and noncurrent
Total debt		$ 14,117,000,000		$ 13,536,000,000	$ 251,000,000	$ 253,000,000	$ 503,000,000	$ 507,000,000	$ 420,000,000	$ 473,000,000	$ 1,120,000,000	$ 1,120,000,000	$ 594,000,000					$ 999,000,000	$ 999,000,000	$ 748,000,000	$ 274,000,000	$ 267,000,000					$ 205,000,000	$ 217,000,000	$ 774,000,000	$ 884,000,000	$ 998,000,000	$ 998,000,000	$ 247,000,000	$ 247,000,000	$ 148,000,000	$ 899,000,000	$ 899,000,000	$ 1,199,000,000	$ 1,199,000,000	$ 745,000,000	$ 97,000,000	$ 97,000,000	$ 57,000,000	$ 57,000,000	$ 311,000,000	$ 311,000,000	$ 664,000,000	$ 676,000,000	$ 598,000,000	$ 598,000,000			$ 30,000,000	$ 1,709,000,000	$ 1,663,000,000	$ 999,000,000	$ 999,000,000	$ 300,000,000	$ 300,000,000				$ 13,912,000,000	$ 12,698,000,000	$ 251,000,000	$ 253,000,000	$ 503,000,000	$ 507,000,000	$ 420,000,000	$ 1,120,000,000	$ 1,120,000,000	$ 594,000,000	$ 999,000,000	$ 999,000,000	$ 748,000,000	$ 274,000,000	$ 267,000,000	$ 774,000,000	$ 884,000,000	$ 998,000,000	$ 998,000,000	$ 247,000,000	$ 247,000,000	$ 899,000,000	$ 899,000,000	$ 1,199,000,000	$ 1,199,000,000	$ 745,000,000	$ 97,000,000	$ 97,000,000	$ 57,000,000	$ 57,000,000	$ 311,000,000	$ 311,000,000	$ 664,000,000	$ 676,000,000	$ 598,000,000	$ 598,000,000	$ 30,000,000	$ 1,709,000,000	$ 1,663,000,000	$ 999,000,000	$ 999,000,000	$ 300,000,000	$ 300,000,000		$ 205,000,000	$ 838,000,000	$ 473,000,000	$ 205,000,000	$ 217,000,000	$ 148,000,000
Debt due within one year		2,729,000,000		2,187,000,000	251,000,000		503,000,000		70,000,000	70,000,000			90,000,000														28,000,000	27,000,000	148,000,000	142,000,000					148,000,000												20,000,000	17,000,000					30,000,000	1,709,000,000	1,663,000,000								2,701,000,000	1,942,000,000	251,000,000		503,000,000		70,000,000			90,000,000						148,000,000	142,000,000																20,000,000	17,000,000			30,000,000	1,709,000,000	1,663,000,000						28,000,000	245,000,000	70,000,000	28,000,000	27,000,000	148,000,000
Long-term debt		11,388,000,000		11,349,000,000																																																											11,211,000,000	10,756,000,000																																											177,000,000	593,000,000
Debt instrument interest rate stated percentage					5.00%		5.25%				4.95%							5.05%		2.50%					11.00%	11.00%					6.00%		7.375%			6.50%		6.375%		3.80%	7.45%		8.00%		7.00%				7.50%			1.50%		1.50%		6.80%		7.35%
Percentage ownership interest in Transocean Inc. by Transocean Ltd.																																																																																																										100.00%
Credit facility term																																																												5 years
Borrowing capacity, maximum														500,000,000																																														2,000,000,000																																																					1,265,000,000				75,000,000		215,000,000	399,000,000	90,000,000
Weighted-average interest rate (as a percent)																																																																																																																	2.00%						1.50%		3.50%
Debt instrument face amount																	400,000,000																																																																																																		1,000,000,000	190,000,000
Commitment fee percentage at period end																																																												0.275%	0.125%	0.325%
Credit facility available borrowing capacity																																																												2,000,000,000
Letters of credit issued and outstanding																																																												24,000,000																																																										60,000,000
Principal amount		14,104,000,000																					164,000,000	940,000,000	98,000,000	560,000,000																											30,000,000	1,722,000,000	1,722,000,000								13,899,000,000																																												205,000,000												177,000,000
Aggregate principal amount of notes issued																				750,000,000																				750,000,000
Redemption price of debt instrument (as a percent)																				100.00%																				100.00%
Aggregate principal amount outstanding		14,104,000,000																		750,000,000																				750,000,000																							13,899,000,000																																												205,000,000
Credit facility amount outstanding																																																																																																																	840,000,000								80,000,000
Debt due to a subsidiary, eliminated in consolidation																																																																																																																	420,000,000							399,000,000	52,000,000
Prepayment of debt	148,000,000														173,000,000	333,000,000																																			30,000,000
Loss on retirement of debt															1,000,000	2,000,000
Restricted investments used as security for debt instruments																													778,000,000	889,000,000																																																																																			23,000,000	23,000,000							31,000,000	16,000,000
NOK exchange rate			5.73
Weighted-average interest rate (as a percent)																							9.10%	9.10%
Ownership interest in affiliate (as a percent)																																																																																																																									65.00%