1.0.0.3 true CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY AND COMPREHENSIVE INCOME (USD $) In Millions false 1 $ true false false false Additional Paid-in Capital us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AdditionalPaidInCapitalMember us-gaap_StatementEquityComponentsAxis explicitMember Unit_1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 2 $ true false false false Common Stock us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_CommonStockMember us-gaap_StatementEquityComponentsAxis explicitMember Unit_9 Standard http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ true false false false Treasury Stock us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_TreasuryStockMember us-gaap_StatementEquityComponentsAxis explicitMember Unit_1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 4 $ true false false false Retained Earnings us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_RetainedEarningsMember us-gaap_StatementEquityComponentsAxis explicitMember Unit_1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 5 $ true false false false Accumulated Other Comprehensive Income us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AccumulatedOtherComprehensiveIncomeMember us-gaap_StatementEquityComponentsAxis explicitMember Unit_1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 6 $ false false Unit_1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit_2 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit_9 Standard http://www.xbrl.org/2003/instance shares xbrli 0 6 Begining shares at Sep. 30, 2006 4 us-gaap_CommonStockSharesOutstanding us-gaap true na instant shares No definition available. false false false true false false true false false 1 false false 0 0 true false 2 false true 720500000 720 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 12 Beginning balance at Sep. 30, 2006 4 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false true false false true false false 1 true true 1864200000 1864 true false 2 false false 0 0 true false 3 true true -2603600000 -2604 true false 4 true true 2774900000 2775 true false 5 true true 6400000 6 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 5 Common stock, shares issued 3 us-gaap_IncreaseDecreaseInStockholdersEquityRollForward us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. false 7 Employee stock plans 4 us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans us-gaap true na duration shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 3600000 4 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 8 Debentures converted 4 us-gaap_DebtConversionConvertedInstrumentSharesIssued us-gaap true na instant shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 7300000 7 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 9 Treasury share retirement 4 us-gaap_TreasuryStockSharesRetired us-gaap true na duration shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 11 Common stock, par value 4 us-gaap_CommonStockParOrStatedValuePerShare us-gaap true na instant decimal No definition available. false false false false false false false false true 1 false false 0 0 true false 2 true true 0.1 0.1 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 13 Proceeds from stock plans 4 us-gaap_ProceedsFromStockPlans us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 65500000 66 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 14 Share-based compensation 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 35700000 36 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 15 Tax benefit on share-based compensation 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 26200000 26 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 16 Debentures converted 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 48700000 49 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 17 Purchase of note hedges 4 igt_AdjustmentsToAdditionalPaidInCapitalConveritbleNoteHedge igt false credit duration monetary Adjustment to Additional Paid in Capital resulting from the purchase of convertible note hedge. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Adjustment to Additional Paid in Capital resulting from the purchase of convertible note hedge. No authoritative reference available. false 18 Tax benefit on note hedges 4 igt_AdjustmentsToAdditionalPaidInCapitalTaxBenefitOnConvertibleNoteHedge igt false credit duration monetary Adjustment to Additional Paid in Capital resulting from the tax benefit on convertible note hedge. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Adjustment to Additional Paid in Capital resulting from the tax benefit on convertible note hedge. No authoritative reference available. false 19 Proceeds from sale of warrants 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 20 Treasury shares acquired 4 us-gaap_TreasuryStockValueAcquiredCostMethod us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true -1118500000 -1118 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 21 RSA forfeitures 4 igt_TreasuryStockValueRestrictedStockAwardForfeited igt false debit duration monetary Number of treasury shares related to restricted stock award forfeited during the period. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Number of treasury shares related to restricted stock award forfeited during the period. No authoritative reference available. false 22 Treasury share retirement 4 us-gaap_TreasuryStockValueRetiredCostMethod us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false true 0 0 true false 4 false true 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 23 Dividends declared 4 us-gaap_DividendsCommonStockCash us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -174700000 -175 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 24 Net income 4 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 508200000 508 true false 5 false false 0 0 true false 6 false true 508200000 508 false false No definition available. No authoritative reference available. false 25 Adoption of guidance for uncertianty in income taxes 4 us-gaap_CumulativeEffectOfInitialAdoptionOfFIN48 us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 26 Other comprehensive income (loss) 4 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 19600000 20 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 27 Unrealized gains (losses) on securities 4 us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 3900000 4 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 28 Foreign currency translation 4 us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 22100000 22 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 10 Ending shares at Sep. 30, 2007 4 us-gaap_CommonStockSharesOutstanding us-gaap true na instant shares No definition available. false false false true false false false true false 1 false false 0 0 true false 2 false true 731400000 731 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 32 Ending balance at Sep. 30, 2007 4 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false true false false false true false 1 false true 2040300000 2040 true false 2 false false 0 0 true false 3 false true -3722100000 -3722 true false 4 false true 3108400000 3108 true false 5 false true 26000000 26 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 5 Common stock, shares issued 3 us-gaap_IncreaseDecreaseInStockholdersEquityRollForward us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. false 7 Employee stock plans 4 us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans us-gaap true na duration shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 3500000 4 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 8 Debentures converted 4 us-gaap_DebtConversionConvertedInstrumentSharesIssued us-gaap true na instant shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 9 Treasury share retirement 4 us-gaap_TreasuryStockSharesRetired us-gaap true na duration shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true -400000000 -400 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 11 Common stock, par value 4 us-gaap_CommonStockParOrStatedValuePerShare us-gaap true na instant decimal No definition available. false false false false false false false false true 1 false false 0 0 true false 2 true true 0.1 0.1 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 true true 0.00016 0.00016 false false No definition available. No authoritative reference available. true 13 Proceeds from stock plans 4 us-gaap_ProceedsFromStockPlans us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 70900000 71 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 14 Share-based compensation 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 38400000 38 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 15 Tax benefit on share-based compensation 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 18000000 18 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 16 Debentures converted 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 17 Purchase of note hedges 4 igt_AdjustmentsToAdditionalPaidInCapitalConveritbleNoteHedge igt false credit duration monetary Adjustment to Additional Paid in Capital resulting from the purchase of convertible note hedge. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Adjustment to Additional Paid in Capital resulting from the purchase of convertible note hedge. No authoritative reference available. false 18 Tax benefit on note hedges 4 igt_AdjustmentsToAdditionalPaidInCapitalTaxBenefitOnConvertibleNoteHedge igt false credit duration monetary Adjustment to Additional Paid in Capital resulting from the tax benefit on convertible note hedge. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Adjustment to Additional Paid in Capital resulting from the tax benefit on convertible note hedge. No authoritative reference available. false 19 Proceeds from sale of warrants 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 20 Treasury shares acquired 4 us-gaap_TreasuryStockValueAcquiredCostMethod us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true -779700000 -780 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 21 RSA forfeitures 4 igt_TreasuryStockValueRestrictedStockAwardForfeited igt false debit duration monetary Number of treasury shares related to restricted stock award forfeited during the period. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true -1000000 -1 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Number of treasury shares related to restricted stock award forfeited during the period. No authoritative reference available. false 22 Treasury share retirement 4 us-gaap_TreasuryStockValueRetiredCostMethod us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -905600000 -906 true false 2 false false 0 0 true false 3 false true 3704300000 3704 true false 4 false true -2798700000 -2799 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 23 Dividends declared 4 us-gaap_DividendsCommonStockCash us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -174200000 -174 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 24 Net income 4 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 342500000 342 true false 5 false false 0 0 true false 6 false true 342500000 342 false false No definition available. No authoritative reference available. false 25 Adoption of guidance for uncertianty in income taxes 4 us-gaap_CumulativeEffectOfInitialAdoptionOfFIN48 us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -34500000 -34 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 26 Other comprehensive income (loss) 4 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true -24100000 -24 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 27 Unrealized gains (losses) on securities 4 us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true -3300000 -3 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 28 Foreign currency translation 4 us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 5200000 5 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 10 Ending shares at Sep. 30, 2008 4 us-gaap_CommonStockSharesOutstanding us-gaap true na instant shares No definition available. false false false true false false false true false 1 false false 0 0 true false 2 false true 334900000 335 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false true 294700000 295 false false No definition available. No authoritative reference available. false 32 Ending balance at Sep. 30, 2008 4 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false true false false false true false 1 false true 1262000000 1262 true false 2 false false 0 0 true false 3 false true -798500000 -798 true false 4 false true 443500000 444 true false 5 false true 1900000 2 true false 6 false true 909000000 909 false false No definition available. No authoritative reference available. false 5 Common stock, shares issued 3 us-gaap_IncreaseDecreaseInStockholdersEquityRollForward us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. false 7 Employee stock plans 4 us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans us-gaap true na duration shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 2300000 2 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 8 Debentures converted 4 us-gaap_DebtConversionConvertedInstrumentSharesIssued us-gaap true na instant shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 9 Treasury share retirement 4 us-gaap_TreasuryStockSharesRetired us-gaap true na duration shares No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false true 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 11 Common stock, par value 4 us-gaap_CommonStockParOrStatedValuePerShare us-gaap true na instant decimal No definition available. false false false false false false false false true 1 false false 0 0 true false 2 true true 0.1 0.1 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 true true 0.00016 0.00016 false false No definition available. No authoritative reference available. true 13 Proceeds from stock plans 4 us-gaap_ProceedsFromStockPlans us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 13400000 13 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 14 Share-based compensation 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 39000000 39 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 15 Tax benefit on share-based compensation 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -5000000 -5 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 16 Debentures converted 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 17 Purchase of note hedges 4 igt_AdjustmentsToAdditionalPaidInCapitalConveritbleNoteHedge igt false credit duration monetary Adjustment to Additional Paid in Capital resulting from the purchase of convertible note hedge. false false false false false false false false false 1 false true -177300000 -177 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Adjustment to Additional Paid in Capital resulting from the purchase of convertible note hedge. No authoritative reference available. false 18 Tax benefit on note hedges 4 igt_AdjustmentsToAdditionalPaidInCapitalTaxBenefitOnConvertibleNoteHedge igt false credit duration monetary Adjustment to Additional Paid in Capital resulting from the tax benefit on convertible note hedge. false false false false false false false false false 1 false true 65200000 65 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Adjustment to Additional Paid in Capital resulting from the tax benefit on convertible note hedge. No authoritative reference available. false 19 Proceeds from sale of warrants 4 us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 66800000 67 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 20 Treasury shares acquired 4 us-gaap_TreasuryStockValueAcquiredCostMethod us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 21 RSA forfeitures 4 igt_TreasuryStockValueRestrictedStockAwardForfeited igt false debit duration monetary Number of treasury shares related to restricted stock award forfeited during the period. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true -800000 -1 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false Number of treasury shares related to restricted stock award forfeited during the period. No authoritative reference available. false 22 Treasury share retirement 4 us-gaap_TreasuryStockValueRetiredCostMethod us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 true false 2 false false 0 0 true false 3 false true 0 0 true false 4 false true 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 23 Dividends declared 4 us-gaap_DividendsCommonStockCash us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -96200000 -96 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 24 Net income 4 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 149000000 149 true false 5 false false 0 0 true false 6 false true 149000000 149 false false No definition available. No authoritative reference available. false 25 Adoption of guidance for uncertianty in income taxes 4 us-gaap_CumulativeEffectOfInitialAdoptionOfFIN48 us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 0 0 true false 5 false false 0 0 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 26 Other comprehensive income (loss) 4 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 4200000 4 true false 6 false false 0 0 false false No definition available. No authoritative reference available. true 27 Unrealized gains (losses) on securities 4 us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 4200000 4 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 28 Foreign currency translation 4 us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 1900000 2 true false 6 false false 0 0 false false No definition available. No authoritative reference available. false 10 Ending shares at Sep. 30, 2009 4 us-gaap_CommonStockSharesOutstanding us-gaap true na instant shares No definition available. false false false true false false false true false 1 false false 0 0 true false 2 false true 337200000 337 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false true 296600000 297 false false No definition available. No authoritative reference available. false 32 Ending balance at Sep. 30, 2009 4 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false true false false false true false 1 true true 1264100000 1264 true false 2 false false 0 0 true false 3 true true -799300000 -799 true false 4 true true 496300000 496 true false 5 true true 6100000 6 true false 6 true true 967300000 967 false false No definition available. No authoritative reference available. false false 6 71 false Millions Millions Millions false true