v2.4.0.6

Unaudited Condensed Consolidated Financial Statements (Details) (USD $)	3 Months Ended
	Mar. 31, 2011	Apr. 25, 2011
Unaudited Condensed Consolidated Financial Statements [Abstract]
Cash that company can convert to through ownership of outstanding shares	$ 15.60
Number of ads that company can convert to through ownership of outstanding shares.	0.4778
Business acquisition, contingent consideration, potential cash payment	2,800,000,000
Business acquisition, equity interest issued or issuable, number of shares	86,000,000
Business acquisition, contingent consideration, at fair value	7,900,000,000
Business acquisition, equity interest issued or issuable, value assigned	5,100,000,000
Closing price of stock		59.10
Estimated fair value of stock acquired by company	$ 32,000,000

X

- Definition

Cash That Company Can Convert To Through Ownership Of Outstanding Shares

+ References

No definition available.

+ Details

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Namespace Prefix:	esv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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X

- Definition

Closing Price of Stock

+ References

No definition available.

+ Details

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Namespace Prefix:	esv_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Estimated Fair Value of Stock Acquired by Company

+ References

No definition available.

+ Details

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Namespace Prefix:	esv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Number of ads that company can convert to through ownership of outstanding shares.

+ References

No definition available.

+ Details

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Namespace Prefix:	esv_
Data Type:	xbrli:sharesItemType
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- Details

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X

- Definition

Fair value, as of the acquisition date, of potential payments under the contingent consideration arrangement including cash and shares.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph g(1)



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph f



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 29, 30, 41, 42, 64



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 65

-Subparagraph a, b

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of potential cash payments that could result from the contingent consideration arrangement.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph f

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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X

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ 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

+ Details

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X

- Definition

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ 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 Emerging Issues Task Force (EITF)

-Number 99-12

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