2.2.0.25falsefalse088 - Statement - Earnings Per Share (Detail)truefalseIn Millions, except Per Share datafalse1falsefalseUSDfalsefalse10/1/2009 - 9/30/2010 USD ($) / shares USD ($) $c0_From1Oct2009To30Sep2010http://www.sec.gov/CIK0000353944duration2009-10-01T00:00:002010-09-30T00:00:00ratioStandardhttp://www.xbrl.org/2003/instancepurexbrli0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2falsefalseUSDfalsefalse10/1/2008 - 9/30/2009 USD ($) USD ($) / shares $c1_From1Oct2008To30Sep2009http://www.sec.gov/CIK0000353944duration2008-10-01T00:00:002009-09-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0ratioStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$3falsefalseUSDfalsefalse10/1/2007 - 9/30/2008 USD ($) USD ($) / shares $c2_From1Oct2007To30Sep2008http://www.sec.gov/CIK0000353944duration2007-10-01T00:00:002008-09-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170ratioStandardhttp://www.xbrl.org/2003/instancepurexbrli0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0us-gaap_EarningsPerShareAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseEarnings Per Share [Abstract]3false0us-gaap_IncomeLossFromContinuingOperationsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse224300000224.3[1]falsetruefalsefalsefalse2truefalsefalse152500000152.5[1]falsetruefalsefalsefalse3truefalsefalse334300000334.3[1]falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the income or loss from continuing operations attributable to the reporting entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items and cumulative effects of changes in accounting principles, but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests, if any.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 28 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph b(1) falsefalseIncome from continuing operations available to common shares (1) (in Dollars)4false0us-gaap_WeightedAverageNumberOfSharesOutstandingBasicus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse296300000296.3falsefalsefalsefalsefalse2truefalsefalse293800000293.8falsefalsefalsefalsefalse3truefalsefalse308000000308.0falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of [basic] shares, after adjustment for contingently issuable shares and other shares not deemed outstanding, determined by relating the portion of time within a reporting period that common shares have been outstanding to the total time in that period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 171 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph a Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 8 falsefalseBasic weighted average shares outstanding5false0us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangementsus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse15000001.5falsefalsefalsefalsefalse2truefalsefalse2000000.2falsefalsefalsefalsefalse3truefalsefalse22000002.2falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesAggregate awards of share options and nonvested shares to be issued to an employee under a share-based compensation arrangement are considered options for purposes of computing diluted earnings per share. Such share-based awards shall be considered to be outstanding as of the grant date for purposes of computing diluted earnings per share even though their exercise may be contingent upon vesting. Those share-based awards are included in the diluted Earnings Per Share (EPS) computation even if the employee may not receive (or be able to sell) the stock until some future date. Accordingly, all shares to be issued shall be included in computing diluted EPS if the effect is dilutive. The dilutive effect of share-based compensation arrangements shall be computed using the treasury stock method. If the equity share options or other equity instruments are outstanding for only part of a period, the shares issuable shall be weighted to reflect the portion of the period during which the equity instruments were outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 20 falsefalseDilutive effect of non-participating share-based awards6false0us-gaap_WeightedAverageNumberOfDilutedSharesOutstandingus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse297800000297.8falsefalsefalsefalsefalse2truefalsefalse294000000294.0falsefalsefalsefalsefalse3truefalsefalse310200000310.2falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesThe average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph a Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 8 falsefalseDiluted weighted average common shares outstanding7false0us-gaap_IncomeLossFromContinuingOperationsPerBasicShareus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse0.750.75falsetruefalsefalsefalse2truefalsefalse0.520.52falsetruefalsefalsefalse3truefalsefalse1.071.07falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalThe amount of income (loss) from continuing operations per each share of common stock outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 36, 37, 38 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 falsetrueBasic earnings per share from continuing operations (in Dollars per share)8false0us-gaap_IncomeLossFromContinuingOperationsPerDilutedShareus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse0.750.75falsetruefalsefalsefalse2truefalsefalse0.520.52falsetruefalsefalsefalse3truefalsefalse1.061.06falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalThe amount of income (loss) from continuing operations available to each share of common stock outstanding during the reporting period and each share that would have been outstanding assuming the issuance of common shares for all dilutive potential common shares outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 11, 12, 36, 37, 38 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph a Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 falsetrueDiluted earnings per share from continuing operations (in Dollars per share)9true0igt_WeightedAverageSharesExcludedFromDilutedEpsBecauseTheEffectWouldBeAntiDilutiveAbstractigtfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseWeighted average shares excluded from diluted EPS because the effect would be anti-dilutive:10false0igt_SharebasedAwardsigtfalsenadurationAntidilutive securities excluded from computation of earnings per share, by antidilutive securities, stock options.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse1230000012.3falsefalsefalsefalsefalse2truefalsefalse1590000015.9falsefalsefalsefalsefalse3truefalsefalse57000005.7falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesAntidilutive securities excluded from computation of earnings per share, by antidilutive securities, stock options.No authoritative reference available.falsefalseShare-based awards11false0igt_DebenturesigtfalsenadurationAntidilutive securities excluded from computation of earnings per share, by antidilutive securities, convertible debt...falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse1140000011.4falsefalsefalsefalsefalse3truefalsefalse1460000014.6falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesAntidilutive securities excluded from computation of earnings per share, by antidilutive securities, convertible debt securities.No authoritative reference available.falsefalseDebentures12false0igt_NotesigtfalsenadurationNotes that consist of antidilutive securities excluded from computation of earnings per share, by antidilutive 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