Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2011 M subsidiary note jurisdiction employee lawsuit DrillingUnits reduction plaintiff Y VIE	Dec. 31, 2010 DrillingUnits subsidiary
Consolidated variable interest entities
Variable interest entities for which we are the primary beneficiary	2
Carrying amounts associated with consolidated variable interest entities
Assets	$ 2,464	$ 2,462
Liabilities	1,022	1,108
Net carrying amount	1,442	1,354
Unconsolidated Variable interest entities
Number of notes receivable from sale of Midwater Floaters	2
Number of Midwater Floaters sold (in drilling units)		2
Stated interest rate on notes receivable received from sale of Midwater Floaters (as a percent)	9.00%
Stated interest rate on working capital loan (as a percent)	10.00%
Maximum borrowing amount of working capital loan in connection with sale of Midwater Floaters	35
Aggregate carrying amounts of notes receivable in connection with sale of Midwater Floaters	109	109
Aggregate carrying amounts of working capital loan receivable in connection with sale of Midwater Floaters	35	6
TPDI
Carrying amounts associated with consolidated variable interest entities
Assets	1,575	1,598
Liabilities	692	763
Net carrying amount	883	835
ADDCL
Carrying amounts associated with consolidated variable interest entities
Assets	889	864
Liabilities	330	345
Net carrying amount	$ 559	$ 519

- Details

Name:	rig_ConsolidatedVariableInterestEntitiesAbstract
Namespace Prefix:	rig
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum borrowing amount of a working capital loan provided to Awilco Drilling Limited, which is secured by two Midwater Floaters sold to ADL.

+ Details

Name:	rig_MaximumBorrowingAmountOfWorkingCapitalLoanInConnectionWithSaleOfMidwaterFloaters
Namespace Prefix:	rig
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of midwater floaters sold or disposed of in the period.

+ Details

Name:	rig_MidwaterFloatersSold
Namespace Prefix:	rig
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate carrying amount, net of imputed interest, of a note receivable.

+ Details

Name:	rig_NotesReceivableFromRigSale
Namespace Prefix:	rig
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of notes receivable received as non-cash proceeds in connection with the sale of two Midwater Floaters.

+ Details

Name:	rig_NumberOfNotesReceivableFromSaleOfMidwaterFloaters
Namespace Prefix:	rig
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Stated interest rate on notes receivable received from sale of Midwater Floaters.

+ Details

Name:	rig_StatedInterestRateOnNotesReceivableReceivedFromSaleOfMidwaterFloaters
Namespace Prefix:	rig
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the stated interest rate on working capital loan provided by the entity.

+ Details

Name:	rig_StatedInterestRateOnWorkingCapitalLoanReceivable
Namespace Prefix:	rig
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	rig_UnconsolidatedVariableInterestEntitiesAbstract
Namespace Prefix:	rig
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of variable interest entities for which the company is the primary beneficiary.

+ Details

Name:	rig_VariableInterestEntitiesForWhichWeArePrimaryBeneficiary
Namespace Prefix:	rig
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Aggregate carrying amount of working capital loan receivable in connection with the sale of two Midwater Floaters.

+ Details

Name:	rig_WorkingCapitalLoanReceivable
Namespace Prefix:	rig
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Quantifies the net carrying amount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph C6

-Subparagraph c

+ Details

Name:	us-gaap_VariableInterestCarryingAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_VariableInterestCarryingAmountAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Quantifies the net carrying amount of the entity's assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph C6

-Subparagraph c

+ Details

Name:	us-gaap_VariableInterestCarryingAmountAssets
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Quantifies the net carrying amount of the entity's liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph C6

-Subparagraph c

+ Details

Name:	us-gaap_VariableInterestCarryingAmountLiabilities
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant