Represents the number of shares to be purchased pursuant to cash voluntary offer.

Name:	rig_BusinessAcquisitionIrrevocableAgreementNumberOfSharesToBePurchasedPursuantToPrecommitmentAgreement
Namespace Prefix:	rig
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of shares to be acquired pursuant to irrevocable agreement.

+ Details

Name:	rig_BusinessAcquisitionIrrevocableAgreementNumberOfSharesToBePurchasedThroughSubsidiary
Namespace Prefix:	rig
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of total outstanding shares to be purchased from other shareholders.

+ Details

Name:	rig_BusinessAcquisitionIrrevocableAgreementPercentageOfInterestToBeAcquiredFromOtherShareholders
Namespace Prefix:	rig
Data Type:	us-types:percentItemType
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Period Type:	instant

- Definition

Represents the percentage of total outstanding shares to be purchased pursuant to cash voluntary offer.

+ Details

Name:	rig_BusinessAcquisitionIrrevocableAgreementPercentageOfInterestToBeAcquiredPursuantToPrecommitmentAgreement
Namespace Prefix:	rig
Data Type:	us-types:percentItemType
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- Definition

Represents the percentage of total outstanding shares to be purchased pursuant to irrevocable agreement.

+ Details

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Namespace Prefix:	rig
Data Type:	us-types:percentItemType
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Period Type:	instant

- Definition

Percentage of voting interest to be acquired in the business combination.

+ Details

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

- Definition

Percentage of voting equity interest to be acquired in the business combination under irrevocable commitments.

+ Details

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

- Definition

Represents the per share cash voluntary offer to be paid for entity to be acquired in business combination.

+ Details

Name:	rig_CashVoluntaryOfferPerShareForEntityToBeAcquired
Namespace Prefix:	rig
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of shares of entity to be acquired for which a cash voluntary offer has been submitted.

+ Details

Name:	rig_PercentageOfOwnershipOfEntityToBeAcquired
Namespace Prefix:	rig
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 24

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

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

- Definition

In a business combination achieved in stages, this element represents the acquisition-date percentage of equity in the acquiree held by the acquirer immediately before the acquisition date.

+ Details

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- Definition

Total debt and equity financial instruments including: (1) securities held-to-maturity and (2) securities available-for-sale that will be held for the long-term.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 17

+ Details

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Marketable Security (Details) (Aker Drilling, USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	9 Months Ended				1 Months Ended
	Aug. 31, 2011	Sep. 30, 2011	Aug. 14, 2011	Aug. 14, 2011 Aker Capital AS Irrevocable Agreement	Aug. 14, 2011 Irrevocable Agreement	Sep. 23, 2011 All Cash Voluntary Offer
Business Combination
Percentage of equity held by entity immediately before the acquisition date		0.137
Ownership interest to be acquired in business combination (as a percent)				41.00%
Ownership interest to be acquired in business combination under irrevocable commitment (as a percent)			60.50%
Number of shares to be acquired through one of our subsidiaries				15
Percentage of total outstanding shares to be purchased through one of our subsidiaries				5.00%
Number of shares to be purchased pursuant to pre-commitment agreement				108
Percentage of total outstanding shares to be purchased under pre-commitment agreement				36.00%
Percentage of total outstanding shares to be purchased from other shareholders					19.50%
Percentage of shares for which cash offer has been launched	100.00%	100.00%				100.00%
Value per share at which shares offered under cash voluntary offer (in NOK per share)		$ 26.5				26.5
Aggregate carrying amount of marketable security investment		$ 185
Acquisition costs recognized in general and administrative expense		$ 5