v2.3.0.15

Fair Value Measurements (Summary Of Fair Value Measurements Of Auction Rate Securities Using Significant Level 3 Inputs) (Details) (USD $) In Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010
Fair Value Measurements [Abstract] |  |  |  |  |  |
Beginning Balance | $ 45.2 |  | $ 44.5 |  | $ 60.5 |
Sales | (0.6) |  | (49.3) |  | (16.5) |
Realized losses |  |  | (0.1) | [1] |  |
Unrealized gains | 0.4 | [1] | 4.9 | [1] | 1.0 | [1]
Ending balance | $ 45.0 |  |  |  | $ 45.0 |
[1] | Realized losses and unrealized gains were included in other, net, in our condensed consolidated statements of income.

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- Definition Unrealized gains. + Details
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Namespace Prefix: | esv
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
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Data Type: | xbrli:monetaryItemType
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Period Type: | duration

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- Definition This element represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to assets measured at fair value on a recurring basis using unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(2) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
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Period Type: | instant