$AJG
Arthur J. Gallagher & Co. Stock $ajg

$ajg Overview Financials Valuation SEC Filings Company Website

2012 Q4 Form 10-K Financial Statement

#000119312513046126 Filed on February 08, 2013

Income Statement

Concept	2012 Q4	2012	2011 Q4
Revenue	$673.2M	$2.520B	$578.4M
YoY Change	16.39%	18.06%	25.99%
Cost Of Revenue	$448.2M	$111.6M	$380.6M
YoY Change	17.76%	248.75%	27.29%
Gross Profit	$225.0M	$2.409B	$197.8M
YoY Change	13.75%	14.55%	23.55%
Gross Profit Margin	33.42%	95.57%	34.2%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$36.70M	$41.40M	$33.90M
YoY Change	8.26%	15.32%	40.66%
% of Gross Profit	16.31%	1.72%	17.14%
Operating Expenses	$168.7M	$483.2M	$140.0M
YoY Change	20.5%	15.32%	11.46%
Operating Profit	$56.30M	$1.926B	$57.80M
YoY Change	-2.6%	14.36%	67.54%
Interest Expense	-$10.90M	$43.00M	-$10.40M
YoY Change	4.81%	5.39%	19.54%
% of Operating Profit	-19.36%	2.23%	-17.99%
Other Income/Expense, Net
YoY Change
Pretax Income	$45.40M	$245.3M	$47.40M
YoY Change	-4.22%	18.05%	83.72%
Income Tax	$11.90M	$50.30M	$6.900M
% Of Pretax Income	26.21%	20.51%	14.56%
Net Earnings	$33.50M	$195.0M	$40.50M
YoY Change	-17.28%	35.32%	-25.96%
Net Earnings / Revenue	4.98%	7.74%	7.0%
Basic Earnings Per Share	$0.27	$1.61	$0.36
Diluted Earnings Per Share	$0.27	$1.59	$0.35
COMMON SHARES
Basic Shares Outstanding		121.0M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2012 Q4	2012	2011 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments	$302.0M	$302.0M	$291.0M
YoY Change	3.78%	3.78%	16.4%
Cash & Equivalents	$302.1M	$302.0M	$291.2M
Short-Term Investments
Other Short-Term Assets	$179.7M	$1.031B	$188.6M
YoY Change	-4.72%	17.03%	-74.02%
Inventory
Prepaid Expenses
Receivables		$1.096B
Other Receivables		$0.00
Total Short-Term Assets	$2.430B	$2.430B	$2.199B
YoY Change	10.46%	10.5%	27.43%
LONG-TERM ASSETS
Property, Plant & Equipment	$105.4M	$105.0M	$91.30M
YoY Change	15.44%	15.38%	20.13%
Goodwill	$1.473B		$1.155B
YoY Change	27.47%		30.73%
Intangibles	$809.6M		$561.5M
YoY Change	44.19%		16.13%
Long-Term Investments
YoY Change
Other Assets	$283.3M	$535.0M	$235.8M
YoY Change	20.14%	12.39%	-44.78%
Total Long-Term Assets	$2.923B	$2.922B	$2.284B
YoY Change	27.96%	27.88%	22.14%
TOTAL ASSETS
Total Short-Term Assets	$2.430B	$2.430B	$2.199B
Total Long-Term Assets	$2.923B	$2.922B	$2.284B
Total Assets	$5.352B	$5.352B	$4.484B
YoY Change	19.38%	19.36%	24.68%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$1.820B	$1.820B	$1.622B
YoY Change	12.21%	12.21%	29.76%
Accrued Expenses	$307.0M	$307.0M	$304.0M
YoY Change	0.99%	0.99%	33.92%
Deferred Revenue
YoY Change
Short-Term Debt	$129.0M	$0.00	$10.00M
YoY Change	1190.0%
Long-Term Debt Due	$129.0M	$129.0M	$10.00M
YoY Change	1190.0%	1190.0%
Total Short-Term Liabilities	$2.363B	$2.363B	$2.074B
YoY Change	13.95%	13.93%	31.49%
LONG-TERM LIABILITIES
Long-Term Debt	$725.0M	$725.0M	$675.0M
YoY Change	7.41%	7.41%	22.73%
Other Long-Term Liabilities	$605.8M	$606.0M	$491.3M
YoY Change	23.31%	23.42%	35.72%
Total Long-Term Liabilities	$1.331B	$1.331B	$1.166B
YoY Change	14.1%	14.15%	27.88%
TOTAL LIABILITIES
Total Short-Term Liabilities	$2.363B	$2.363B	$2.074B
Total Long-Term Liabilities	$1.331B	$1.331B	$1.166B
Total Liabilities	$3.694B	$3.694B	$3.240B
YoY Change	14.01%	14.01%	30.17%
SHAREHOLDERS EQUITY
Retained Earnings	$510.4M		$482.9M
YoY Change	5.69%
Common Stock	$1.181B		$807.9M
YoY Change	46.18%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.659B	$1.659B	$1.244B
YoY Change
Total Liabilities & Shareholders Equity	$5.352B	$5.352B	$4.484B
YoY Change	19.38%	19.36%	24.68%

Cashflow Statement

Concept	2012 Q4	2012	2011 Q4
OPERATING ACTIVITIES
Net Income	$33.50M	$195.0M	$40.50M
YoY Change	-17.28%	35.32%	-25.96%
Depreciation, Depletion And Amortization	$36.70M	$41.40M	$33.90M
YoY Change	8.26%	15.32%	40.66%
Cash From Operating Activities	$163.6M	$343.0M	$98.40M
YoY Change	66.26%	20.77%	475.44%
INVESTING ACTIVITIES
Capital Expenditures	-$14.90M	$51.00M	-$10.60M
YoY Change	40.57%	11.11%	51.43%
Acquisitions		$344.1M
YoY Change		29.95%
Other Investing Activities	-$212.9M	-$331.2M	-$32.50M
YoY Change	555.08%	24.84%	-10.71%
Cash From Investing Activities	-$227.8M	-$382.2M	-$43.10M
YoY Change	428.54%	22.81%	-0.69%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		-$80.80M
YoY Change		11.14%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	61.00M	45.90M	-6.700M
YoY Change	-1010.45%	-30.03%	-71.37%
NET CHANGE
Cash From Operating Activities	163.6M	343.0M	98.40M
Cash From Investing Activities	-227.8M	-382.2M	-43.10M
Cash From Financing Activities	61.00M	45.90M	-6.700M
Net Change In Cash	-3.200M	6.700M	48.60M
YoY Change	-106.58%	-82.55%	-197.79%
FREE CASH FLOW
Cash From Operating Activities	$163.6M	$343.0M	$98.40M
Capital Expenditures	-$14.90M	$51.00M	-$10.60M
Free Cash Flow	$178.5M	$292.0M	$109.0M
YoY Change	63.76%	22.64%	352.28%

Facts In Submission

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CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	9000000	shares
CY2012Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	363800000
CY2012Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	320200000
CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Property Plant And Equipment BusinessAcquisitionPurchasePriceAllocationPropertyPlantAndEquipment	4500000
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CY2012Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	851600000
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CY2012Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	125600000	shares
CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Assets Acquired BusinessAcquisitionPurchasePriceAllocationAssetsAcquired	802400000
CY2012Q4	us-gaap	Common Stock Value CommonStockValue	125600000
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CY2012Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	15700000
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CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Current Liabilities BusinessAcquisitionPurchasePriceAllocationCurrentLiabilities	120800000
CY2012Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	52200000
CY2012Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	327600000
CY2012Q4	us-gaap	Goodwill Goodwill	1472700000
CY2012Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	90900000
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CY2012Q4	us-gaap	Long Term Debt LongTermDebt	32400000
CY2012Q4	us-gaap	Defined Benefit Plan Amounts Recognized In Balance Sheet DefinedBenefitPlanAmountsRecognizedInBalanceSheet	26300000
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CY2012Q4	us-gaap	Goodwill Gross GoodwillGross	1472700000
CY2012Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	99600000
CY2012Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	15100000
CY2012Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	9600000
CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Noncurrent Liabilities BusinessAcquisitionPurchasePriceAllocationNoncurrentLiabilities	67300000
CY2012Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	105400000
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	11400000
CY2012Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	125600000	shares
CY2012Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	4500000
CY2012Q4	us-gaap	Finite Lived Trade Names Gross FiniteLivedTradeNamesGross	3100000
CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Liabilities Assumed BusinessAcquisitionPurchasePriceAllocationLiabilitiesAssumed	188100000
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	12200000
CY2012Q4	us-gaap	Assets Current AssetsCurrent	2429500000
CY2012Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	64600000
CY2012Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	227400000
CY2012Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	105000000
CY2012Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	2900000
CY2012Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	129000000
CY2012Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	17100000
CY2012Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	258400000
CY2012Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	725000000
CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	28.76
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	9700000
CY2012Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	110600000
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	72900000
CY2012Q4	ajg	Future Amortization Expense Of Fiscal Year FutureAmortizationExpenseOfFiscalYear	519000000
CY2012Q4	ajg	Semi Annual Payments Of Interest SemiAnnualPaymentsOfInterest	854000000
CY2012Q4	ajg	Self Insurance Deductibles Liability Recorded SelfInsuranceDeductiblesLiabilityRecorded	8500000
CY2012Q4	ajg	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValue	53900000
CY2012Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	600000
CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Current Assets Cash And Cash Equivalents BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents	17300000
CY2012Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	1055400000
CY2012Q4	us-gaap	Stockholders Equity StockholdersEquity	1658600000
CY2012Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	809600000
CY2012Q4	us-gaap	Equity Method Investment Ownership Percentage EquityMethodInvestmentOwnershipPercentage	0.50	pure
CY2012Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	36300000
CY2012Q4	us-gaap	Business Acquisition Purchase Price Allocation Goodwill Amount BusinessAcquisitionPurchasePriceAllocationGoodwillAmount	308800000
CY2012Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet	614300000
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CY2012Q4	ajg	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercised Intrinsic Value SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisedIntrinsicValue	26000000
CY2012Q4	ajg	Unearned Fees UnearnedFees	70600000
CY2012Q4	ajg	Unrecognized Deferred Tax Liability On Undistributed Earnings UnrecognizedDeferredTaxLiabilityOnUndistributedEarnings	22900000
CY2012Q4	ajg	Premiums Payable To Insurance And Reinsurance Companies PremiumsPayableToInsuranceAndReinsuranceCompanies	1819700000
CY2012Q4	ajg	Maximum Potential Earnout Payable MaximumPotentialEarnoutPayable	235200000
CY2012Q4	ajg	Liabilities Recorded On Self Insurance LiabilitiesRecordedOnSelfInsurance	10200000
CY2012Q4	ajg	Expiration Lists ExpirationLists	335500000
CY2012Q4	ajg	Equity Method Investment Summarized Financial Information Funding Commitments EquityMethodInvestmentSummarizedFinancialInformationFundingCommitments	7200000
CY2012Q4	ajg	Business Acquisition Purchase Price Allocation Other Current Assets BusinessAcquisitionPurchasePriceAllocationOtherCurrentAssets	114000000
CY2012Q4	ajg	Deferred Tax Assets Accrued And Unfunded Compensation And Employee Benefits DeferredTaxAssetsAccruedAndUnfundedCompensationAndEmployeeBenefits	107100000
CY2012Q4	ajg	Deferred Tax Assets Accrued Pension Liability DeferredTaxAssetsAccruedPensionLiability	27300000
CY2012Q4	ajg	Deferred Tax Assets Alternative Minimum Tax And Other Credit Carryforwards DeferredTaxAssetsAlternativeMinimumTaxAndOtherCreditCarryforwards	112300000
CY2012Q4	ajg	Deferred Tax Assets Depreciable Fixed Assets DeferredTaxAssetsDepreciableFixedAssets	700000
CY2012Q4	ajg	Deferred Tax Liabilities Accrued Liabilities DeferredTaxLiabilitiesAccruedLiabilities	2000000
CY2012Q4	ajg	Deferred Tax Liabilities Investment Related Partnerships DeferredTaxLiabilitiesInvestmentRelatedPartnerships	17500000
CY2012Q4	ajg	Deferred Tax Liabilities Other Prepaid Items DeferredTaxLiabilitiesOtherPrepaidItems	5200000
CY2012Q4	ajg	Computer Equipment Gross ComputerEquipmentGross	116700000
CY2012Q4	ajg	Accrued Compensation And Other Accrued Liabilities AccruedCompensationAndOtherAccruedLiabilities	306700000
CY2012Q4	ajg	Funding Commitment One FundingCommitmentOne	1500000
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CY2010	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P3Y8M1D
CY2010	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-31000000
CY2010	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	48000000
CY2010	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1500000	shares
CY2010	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-800000
CY2010	us-gaap	Defined Benefit Plan Amortization Of Net Gains Losses DefinedBenefitPlanAmortizationOfNetGainsLosses	-1600000
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	33300000
CY2010	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	2700000
CY2010	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.10
CY2010	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	18400000
CY2010	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	80100000
CY2010	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	11700000
CY2010	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-92600000
CY2010	us-gaap	Income Taxes Paid IncomeTaxesPaid	37600000
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CY2010	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0750	pure
CY2010	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	20.75
CY2010	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	31300000
CY2010	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	600000
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	-0.067	pure
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	169700000
CY2010	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	104800000	shares
CY2010	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.10
CY2010	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	10800000
CY2010	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y1M2D
CY2010	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-7700000
CY2010	us-gaap	Investment Income Net InvestmentIncomeNet	6900000
CY2010	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.196	pure
CY2010	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y1M6D
CY2010	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	1400000
CY2010	us-gaap	Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Cost Expensed BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed	6200000
CY2010	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	136100000
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	203000000
CY2010	us-gaap	Income Tax Expense Benefit Continuing Operations IncomeTaxExpenseBenefitContinuingOperations	39700000
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CY2010	us-gaap	Adjustment For Amortization AdjustmentForAmortization	60800000
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.005	pure
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CY2010	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-300000
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CY2010	us-gaap	Share Based Compensation ShareBasedCompensation	9000000
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CY2010	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	231200000
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.005	pure
CY2010	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	7700000
CY2010	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	800000
CY2010	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	300000	shares
CY2010	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0575	pure
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CY2010	us-gaap	Deferred Compensation Arrangement With Individual Fair Value Of Shares Issued DeferredCompensationArrangementWithIndividualFairValueOfSharesIssued	1000000
CY2010	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	2300000
CY2010	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	5400000
CY2010	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	43900000
CY2010	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	3200000
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.006	pure
CY2010	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	10800000
CY2010	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	81500000
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CY2010	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	111900000
CY2010	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	8800000
CY2010	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	13700000
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CY2010	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	1400000
CY2010	us-gaap	Deferred Compensation Arrangement With Individual Shares Issued DeferredCompensationArrangementWithIndividualSharesIssued	40000	shares
CY2010	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	10000000
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CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	900000	shares
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CY2010	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.66
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CY2010	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.28
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CY2010	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	735000000
CY2010	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	1000000
CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.271	pure
CY2010	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2010	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	-400000
CY2010	us-gaap	Gain Loss On Investments GainLossOnInvestments	5900000
CY2010	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	185300000
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CY2010	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	11300000
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CY2010	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	900000
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CY2010	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	-11500000
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CY2010	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	25100000
CY2010	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	13400000
CY2010	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.56
CY2010	us-gaap	Gain Loss On Sale Of Equity Investments GainLossOnSaleOfEquityInvestments	5900000
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CY2010	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	9300000
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CY2010	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2700000
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CY2010	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	5400000
CY2010	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	36700000
CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.050	pure
CY2010	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	71100000
CY2010	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	21300000
CY2010	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	11	Acquisition
CY2010	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	229500000
CY2010	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-1000000
CY2010	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	-7600000
CY2010	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	-11700000
CY2010	us-gaap	Cost Of Revenue CostOfRevenue	64000000
CY2010	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.56
CY2010	us-gaap	Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	-1600000
CY2010	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.026	pure
CY2010	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1661200000
CY2010	ajg	Number Of Years Options Expire NumberOfYearsOptionsExpire	7	Y
CY2010	ajg	Supplemental Commissions SupplementalCommissions	60800000
CY2010	ajg	Tax Expense From Issuance Of Common Stock TaxExpenseFromIssuanceOfCommonStock	1400000
CY2010	ajg	Tax Impact From Issuance Of Common Stock TaxImpactFromIssuanceOfCommonStock	1400000
CY2010	ajg	Revenues From Clean Coal Activities RevenuesFromCleanCoalActivities	65600000
CY2010	ajg	Other Non Cash Items Related To Discontinued Operations OtherNonCashItemsRelatedToDiscontinuedOperations	12500000
CY2010	ajg	Net Proceeds From Sales Of Operations NetProceedsFromSalesOfOperations	3200000
CY2010	ajg	Net Proceeds Of Investment Transactions NetProceedsOfInvestmentTransactions	9400000
CY2010	ajg	Net Change In Accrued Compensation And Other Accrued Liabilities NetChangeInAccruedCompensationAndOtherAccruedLiabilities	-5900000
CY2010	ajg	Net Change In Fees Receivable Unearned Fees NetChangeInFeesReceivableUnearnedFees	11800000
CY2010	ajg	Income Tax Reconciliation Changes In Unrecognized Tax Benefits Related To Resolution Of Federal And State Audits Expiration Of Various Statutes Of Limitations And Other Items IncomeTaxReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems	-30700000
CY2010	ajg	Income Tax Reconciliation Foreign Dividends And Other Permanent Differences IncomeTaxReconciliationForeignDividendsAndOtherPermanentDifferences	4500000
CY2010	ajg	Change In Estimated Acquisition Earnout Payables ChangeInEstimatedAcquisitionEarnoutPayables	-2600000
CY2010	ajg	Cash And Equity Award With Aggregate Fair Value Vested And Distributed To Participants CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants	1100000
CY2010	ajg	Commissions Commissions	957300000
CY2010	ajg	Amortization Of Deferred Compensation And Restricted Stock AmortizationOfDeferredCompensationAndRestrictedStock	6600000
CY2010	ajg	Deferred Compensation And Restricted Stock DeferredCompensationAndRestrictedStock	6600000
CY2010	ajg	Contingent Commissions ContingentCommissions	36800000
CY2010	ajg	Defined Benefit Plan Minimum Contribution By Employer DefinedBenefitPlanMinimumContributionByEmployer	300000
CY2010	ajg	Defined Benefit Plan Discretionary Contributions By Employer DefinedBenefitPlanDiscretionaryContributionsByEmployer	6500000
CY2010	ajg	Effective Income Tax Rate Reconciliation Changes In Unrecognized Tax Benefits Related To Resolution Of Federal And State Audits Expiration Of Various Statutes Of Limitations And Other Items EffectiveIncomeTaxRateReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems	-0.151	pure
CY2010	ajg	Effective Income Tax Rate Reconciliation Foreign Dividends And Other Permanent Differences EffectiveIncomeTaxRateReconciliationForeignDividendsAndOtherPermanentDifferences	0.022	pure
CY2010	ajg	Options To Purchase Common Stock Shares Outstanding OptionsToPurchaseCommonStockSharesOutstanding	9200000	shares
CY2010	ajg	Weighted Average Number Of Common And Common Equivalent Shares Outstanding WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding	105100000	shares
CY2010	ajg	Additional Equity Compensation Expenses AdditionalEquityCompensationExpenses	1100000
CY2010	ajg	Earnout Obligations Of Acquisitions EarnoutObligationsOfAcquisitions	25	Acquisition
CY2011	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	151000000
CY2011	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P3Y4M28D
CY2011	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-21500000
CY2011	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	141000000
CY2011	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	2600000	shares
CY2011	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	5900000
CY2011	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	8500000
CY2011	us-gaap	Defined Benefit Plan Amortization Of Net Gains Losses DefinedBenefitPlanAmortizationOfNetGainsLosses	-1600000
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	13100000
CY2011	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-52100000
CY2011	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	46200000
CY2011	us-gaap	Goodwill Written Off Related To Sale Of Business Unit GoodwillWrittenOffRelatedToSaleOfBusinessUnit	4300000
CY2011	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	264800000
CY2011	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	8100000
CY2011	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-311200000
CY2011	us-gaap	Income Taxes Paid IncomeTaxesPaid	32000000
CY2011	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	30600000
CY2011	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0750	pure
CY2011	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	25.87
CY2011	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	66700000
CY2011	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	53800000
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	-0.064	pure
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	194700000
CY2011	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	111700000	shares
CY2011	us-gaap	Business Acquisitions Pro Forma Income Loss From Continuing Operations Before Changes In Accounting And Extraordinary Items Net Of Tax BusinessAcquisitionsProFormaIncomeLossFromContinuingOperationsBeforeChangesInAccountingAndExtraordinaryItemsNetOfTax	159300000
CY2011	us-gaap	Business Acquisition Pro Forma Earnings Per Share Basic BusinessAcquisitionProFormaEarningsPerShareBasic	1.35
CY2011	us-gaap	Investment Income Net InvestmentIncomeNet	8100000
CY2011	us-gaap	Debt Instrument Maturity Date DebtInstrumentMaturityDate	2014-07-14
CY2011	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.307	pure
CY2011	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y
CY2011	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	1300000
CY2011	us-gaap	Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Cost Expensed BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed	8300000
CY2011	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	149500000
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	207800000
CY2011	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y9M29D
CY2011	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	24900000
CY2011	us-gaap	Income Tax Expense Benefit Continuing Operations IncomeTaxExpenseBenefitContinuingOperations	63700000
CY2011	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	-300000
CY2011	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	41700000
CY2011	us-gaap	Adjustment For Amortization AdjustmentForAmortization	79300000
CY2011	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	2900000
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.003	pure
CY2011	us-gaap	Interest Paid InterestPaid	38400000
CY2011	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	1800000
CY2011	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	1000000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	21000000
CY2011	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	144100000
CY2011	us-gaap	Share Based Compensation ShareBasedCompensation	14300000
CY2011	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	30.95
CY2011	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	2371000000
CY2011	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	284000000
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.018	pure
CY2011	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	7100000
CY2011	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	1200000
CY2011	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	800000	shares
CY2011	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0550	pure
CY2011	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	41400000
CY2011	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	6900000
CY2011	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	13200000
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.003	pure
CY2011	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	7200000
CY2011	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	91000000
CY2011	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	200000
CY2011	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	102300000
CY2011	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	14500000
CY2011	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	29.03
CY2011	us-gaap	Deferred Compensation Arrangement With Individual Fair Value Of Shares Issued DeferredCompensationArrangementWithIndividualFairValueOfSharesIssued	500000
CY2011	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	4600000
CY2011	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	7200000
CY2011	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax	52200000
CY2011	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.29
CY2011	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	-16100000
CY2011	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y5M1D
CY2011	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	20400000
CY2011	us-gaap	Deferred Compensation Arrangement With Individual Shares Issued DeferredCompensationArrangementWithIndividualSharesIssued	17000	shares
CY2011	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	13100000
CY2011	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	115200000
CY2011	us-gaap	Net Income Loss NetIncomeLoss	144100000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	900000	shares
CY2011	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	246000000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.027	pure
CY2011	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.28
CY2011	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plan Net Transition Asset Obligation Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlanNetTransitionAssetObligationRecognizedInNetPeriodicBenefitCostBeforeTax	51200000
CY2011	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	800000
CY2011	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.32
CY2011	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1200000
CY2011	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	65600000
CY2011	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	870200000
CY2011	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-700000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.268	pure
CY2011	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2011	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	-400000
CY2011	us-gaap	Gain Loss On Investments GainLossOnInvestments	5500000
CY2011	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	94700000
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1200000
CY2011	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	1400000
CY2011	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	7800000
CY2011	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	7200000
CY2011	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	4400000
CY2011	us-gaap	Defined Benefit Plan Amounts That Will Be Amortized From Accumulated Other Comprehensive Income Loss In Next Fiscal Year DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYear	2300000
CY2011	us-gaap	Operating Expenses OperatingExpenses	419000000
CY2011	us-gaap	Revenues Revenues	2134700000
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	900000
CY2011	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-3800000
CY2011	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-200000
CY2011	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	63700000
CY2011	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	3000000
CY2011	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	-55800000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	224000	shares
CY2011	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	-31900000
CY2011	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	45900000
CY2011	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	14900000
CY2011	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	2000000
CY2011	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.28
CY2011	us-gaap	Gain Loss On Sale Of Equity Investments GainLossOnSaleOfEquityInvestments	5500000
CY2011	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	145800000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	200000	shares
CY2011	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	7400000
CY2011	us-gaap	Depreciation Depreciation	35900000
CY2011	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3300000
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	207800000
CY2011	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-3000000
CY2011	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	600000
CY2011	us-gaap	Labor And Related Expense LaborAndRelatedExpense	1326100000
CY2011	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	-8600000
CY2011	us-gaap	Business Acquisition Pro Forma Earnings Per Share Diluted BusinessAcquisitionProFormaEarningsPerShareDiluted	1.35
CY2011	us-gaap	Interest Expense InterestExpense	40800000
CY2011	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-10400000
CY2011	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	9800000
CY2011	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	73900000
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.045	pure
CY2011	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	72700000
CY2011	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	38400000
CY2011	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	22	Acquisition
CY2011	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	284000000
CY2011	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-2700000
CY2011	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	-11900000
CY2011	us-gaap	Cost Of Revenue CostOfRevenue	32000000
CY2011	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.29
CY2011	us-gaap	Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	-1600000
CY2011	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.047	pure
CY2011	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	125000000
CY2011	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1926900000
CY2011	ajg	Number Of Years Options Expire NumberOfYearsOptionsExpire	7	Y
CY2011	ajg	Supplemental Commissions SupplementalCommissions	56000000
CY2011	ajg	Tax Expense From Issuance Of Common Stock TaxExpenseFromIssuanceOfCommonStock	3700000
CY2011	ajg	Tax Impact From Issuance Of Common Stock TaxImpactFromIssuanceOfCommonStock	3700000
CY2011	ajg	Unearned Deferred Compensation Value UnearnedDeferredCompensationValue	6800000
CY2011	ajg	Revenues From Clean Coal Activities RevenuesFromCleanCoalActivities	29200000
CY2011	ajg	Net Proceeds From Sales Of Operations NetProceedsFromSalesOfOperations	14000000
CY2011	ajg	Net Proceeds Of Investment Transactions NetProceedsOfInvestmentTransactions	-14500000
CY2011	ajg	Net Change In Accrued Compensation And Other Accrued Liabilities NetChangeInAccruedCompensationAndOtherAccruedLiabilities	-12800000
CY2011	ajg	Net Change In Fees Receivable Unearned Fees NetChangeInFeesReceivableUnearnedFees	4100000
CY2011	ajg	Income Tax Reconciliation Changes In Unrecognized Tax Benefits Related To Resolution Of Federal And State Audits Expiration Of Various Statutes Of Limitations And Other Items IncomeTaxReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems	-1900000
CY2011	ajg	Income Tax Reconciliation Foreign Dividends And Other Permanent Differences IncomeTaxReconciliationForeignDividendsAndOtherPermanentDifferences	200000
CY2011	ajg	Fair Value Of Funded Cash Award Assets FairValueOfFundedCashAwardAssets	28600000
CY2011	ajg	Goodwill Earnout Adjustments GoodwillEarnoutAdjustments	-30000000
CY2011	ajg	Change In Estimated Acquisition Earnout Payables ChangeInEstimatedAcquisitionEarnoutPayables	-6200000
CY2011	ajg	Cash And Equity Award With Aggregate Fair Value Vested And Distributed To Participants CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants	500000
CY2011	ajg	Commissions Commissions	1127400000
CY2011	ajg	Allowances For Estimated Policy Cancellations AllowancesForEstimatedPolicyCancellations	5200000
CY2011	ajg	Amortization Of Deferred Compensation And Restricted Stock AmortizationOfDeferredCompensationAndRestrictedStock	6800000
CY2011	ajg	Deferred Compensation And Restricted Stock DeferredCompensationAndRestrictedStock	5900000
CY2011	ajg	Contingent Commissions ContingentCommissions	38100000
CY2011	ajg	Defined Benefit Plan Minimum Contribution By Employer DefinedBenefitPlanMinimumContributionByEmployer	300000
CY2011	ajg	Defined Benefit Plan Discretionary Contributions By Employer DefinedBenefitPlanDiscretionaryContributionsByEmployer	7200000
CY2011	ajg	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return On Plan Assets DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnPlanAssets	0.0750	pure
CY2011	ajg	Effective Income Tax Rate Reconciliation Changes In Unrecognized Tax Benefits Related To Resolution Of Federal And State Audits Expiration Of Various Statutes Of Limitations And Other Items EffectiveIncomeTaxRateReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems	-0.009	pure
CY2011	ajg	Effective Income Tax Rate Reconciliation Foreign Dividends And Other Permanent Differences EffectiveIncomeTaxRateReconciliationForeignDividendsAndOtherPermanentDifferences	0.001	pure
CY2011	ajg	Expected Period Of Return On Plan Assets ExpectedPeriodOfReturnOnPlanAssets	10	Y
CY2011	ajg	Options To Purchase Common Stock Shares Outstanding OptionsToPurchaseCommonStockSharesOutstanding	3800000	shares
CY2011	ajg	Weighted Average Number Of Common And Common Equivalent Shares Outstanding WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding	112500000	shares
CY2011	ajg	Unearned Deferred Compensation Share UnearnedDeferredCompensationShare	629000	shares
CY2011	ajg	Earnout Obligations Of Acquisitions EarnoutObligationsOfAcquisitions	19	Acquisition
CY2012	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2012	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2012	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2012
CY2012	dei	Document Type DocumentType	10-K
CY2012	dei	Document Period End Date DocumentPeriodEndDate	2012-12-31
CY2012	dei	Entity Central Index Key EntityCentralIndexKey	0000354190
CY2012	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2012	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2012	dei	Trading Symbol TradingSymbol	AJG
CY2012	dei	Entity Registrant Name EntityRegistrantName	GALLAGHER ARTHUR J & CO
CY2012	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2012	dei	Amendment Flag AmendmentFlag	false
CY2012	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2012	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	303000000
CY2012	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P3Y4M21D
CY2012	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	20400000
CY2012	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	184000000
CY2012	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	2800000	shares
CY2012	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2900000
CY2012	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	-800000
CY2012	us-gaap	Defined Benefit Plan Amortization Of Net Gains Losses DefinedBenefitPlanAmortizationOfNetGainsLosses	-7200000
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	10600000
CY2012	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-11500000
CY2012	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	30800000
CY2012	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	344100000
CY2012	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-52400000
CY2012	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-382200000
CY2012	us-gaap	Income Taxes Paid IncomeTaxesPaid	47500000
CY2012	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	3400000
CY2012	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0750	pure
CY2012	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	26.14
CY2012	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	73900000
CY2012	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	10600000
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	-0.185	pure
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	234700000
CY2012	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	121000000	shares
CY2012	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	Segment
CY2012	us-gaap	Business Acquisitions Pro Forma Income Loss From Continuing Operations Before Changes In Accounting And Extraordinary Items Net Of Tax BusinessAcquisitionsProFormaIncomeLossFromContinuingOperationsBeforeChangesInAccountingAndExtraordinaryItemsNetOfTax	205200000
CY2012	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y6M7D
CY2012	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	33700000
CY2012	us-gaap	Business Acquisition Pro Forma Earnings Per Share Basic BusinessAcquisitionProFormaEarningsPerShareBasic	1.66
CY2012	us-gaap	Investment Income Net InvestmentIncomeNet	10400000
CY2012	us-gaap	Debt Instrument Maturity Date DebtInstrumentMaturityDate	2014-07-14
CY2012	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.205	pure
CY2012	us-gaap	Variable Interest Entity Ownership Percentage VariableInterestEntityOwnershipPercentage	0.50	pure
CY2012	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y
CY2012	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	1200000
CY2012	us-gaap	Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Cost Expensed BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed	9300000
CY2012	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	167500000
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	245300000
CY2012	us-gaap	Income Tax Expense Benefit Continuing Operations IncomeTaxExpenseBenefitContinuingOperations	50300000
CY2012	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	45300000
CY2012	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	-1900000
CY2012	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	20900000
CY2012	us-gaap	Adjustment For Amortization AdjustmentForAmortization	99000000
CY2012	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	25500000
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.001	pure
CY2012	us-gaap	Interest Paid InterestPaid	42200000
CY2012	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	1100000
CY2012	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-4200000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	21100000
CY2012	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	195000000
CY2012	us-gaap	Share Based Compensation ShareBasedCompensation	7500000
CY2012	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	35.71
CY2012	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	2650100000
CY2012	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	343000000
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.006	pure
CY2012	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	7200000
CY2012	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	1500000
CY2012	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1500000	shares
CY2012	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0450	pure
CY2012	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	10900000
CY2012	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	8200000
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.004	pure
CY2012	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	17300000
CY2012	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	91000000
CY2012	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	1400000
CY2012	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	276300000
CY2012	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	5900000
CY2012	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	29.46
CY2012	us-gaap	Deferred Compensation Arrangement With Individual Fair Value Of Shares Issued DeferredCompensationArrangementWithIndividualFairValueOfSharesIssued	700000
CY2012	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	3500000
CY2012	us-gaap	Basis Of Accounting BasisOfAccounting	<div> <p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px"><font style="FONT-FAMILY: Times New Roman" size="2"><b>Basis of Presentation -</b> The accompanying consolidated financial statements include our accounts and all of our majority-owned subsidiaries (50% or greater ownership). Substantially all of our investments in partially owned entities in which our ownership is less than 50% are accounted for using the equity method based on the legal form of our ownership interest and the applicable ownership percentage of the entity. However, in situations where a less than 50%-owned investment has been determined to be a variable interest entity (which we refer to as a VIE) and we are deemed to be the primary beneficiary in accordance with the variable interest model of consolidation, we will consolidate the investment into our consolidated financial statements. For partially owned entities accounted for using the equity method, our share of the net earnings of these entities is included in consolidated net earnings. All material intercompany accounts and transactions have been eliminated in consolidation.</font></p> <p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px"><font style="FONT-FAMILY: Times New Roman" size="2">Certain reclassifications have been made to the amounts reported in prior years’ consolidated financial statements in order to conform to the current year presentation.</font></p> <p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px"><font style="FONT-FAMILY: Times New Roman" size="2">In the preparation of our consolidated financial statements as of December 31, 2012, management evaluated all material subsequent events or transactions that occurred after the balance sheet date through the date on which the financial statements were issued for potential recognition in our consolidated financial statements and/or disclosure in the notes thereto.</font></p> </div>
CY2012	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	8400000
CY2012	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax	3400000
CY2012	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.61
CY2012	us-gaap	Nature Of Operations NatureOfOperations	<div> <p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px"><font style="FONT-FAMILY: Times New Roman" size="2"><b>Nature of Operations -</b> Arthur J. Gallagher & Co. and its subsidiaries, collectively referred to herein as we, our or us, provide insurance brokerage and risk management services to a wide variety of commercial, industrial, institutional and governmental organizations through two reportable operating segments. Commission and fee revenue generated by the brokerage segment is primarily related to the negotiation and placement of insurance for our clients. Fee revenue generated by the risk management segment is primarily related to claims management, information management, risk control consulting (loss control) services and appraisals in the property/casualty market. Investment income and other revenue is generated from our investment portfolio, which includes invested cash and restricted funds, as well as tax-advantaged, clean energy and other investments. We are headquartered in Itasca, Illinois, have operations in 18 countries and offer client-service capabilities in more than 140 countries globally through a network of correspondent insurance brokers and consultants.</font></p> </div>
CY2012	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	16100000
CY2012	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y4M28D
CY2012	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	200000
CY2012	us-gaap	Deferred Compensation Arrangement With Individual Shares Issued DeferredCompensationArrangementWithIndividualSharesIssued	19000	shares
CY2012	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	14400000
CY2012	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	140400000
CY2012	us-gaap	Net Income Loss NetIncomeLoss	195000000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	1400000	shares
CY2012	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	308800000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.012	pure
CY2012	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.59
CY2012	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plan Net Transition Asset Obligation Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlanNetTransitionAssetObligationRecognizedInNetPeriodicBenefitCostBeforeTax	7600000
CY2012	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.36
CY2012	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1500000
CY2012	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	45900000
CY2012	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	971700000
CY2012	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	300000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.269	pure
CY2012	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2012	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	-400000
CY2012	us-gaap	Gain Loss On Investments GainLossOnInvestments	3900000
CY2012	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	209400000
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1700000
CY2012	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	1600000
CY2012	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	45400000
CY2012	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	7200000
CY2012	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	5100000
CY2012	us-gaap	Defined Benefit Plan Amounts That Will Be Amortized From Accumulated Other Comprehensive Income Loss In Next Fiscal Year DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYear	7700000
CY2012	us-gaap	Operating Expenses OperatingExpenses	483200000
CY2012	us-gaap	Revenues Revenues	2520300000
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1100000
CY2012	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	1200000
CY2012	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-1900000
CY2012	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	50300000
CY2012	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	4200000
CY2012	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	33300000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	352000	shares
CY2012	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	90200000
CY2012	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	51000000
CY2012	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	15200000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Maximum Number Of Shares Per Employee ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee	200000	shares
CY2012	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	300000
CY2012	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.59
CY2012	us-gaap	Gain Loss On Sale Of Equity Investments GainLossOnSaleOfEquityInvestments	3900000
CY2012	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	130000000
CY2012	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	204400000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	200000	shares
CY2012	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	8700000
CY2012	us-gaap	Depreciation Depreciation	41400000
CY2012	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	4200000
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	245300000
CY2012	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-3600000
CY2012	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	900000
CY2012	us-gaap	Labor And Related Expense LaborAndRelatedExpense	1493400000
CY2012	us-gaap	Use Of Estimates UseOfEstimates	<div> <p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px"><font style="FONT-FAMILY: Times New Roman" size="2"><b>Use of Estimates</b> - The preparation of our consolidated financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Such estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed herein.</font></p> </div>
CY2012	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	9300000
CY2012	us-gaap	Business Acquisition Pro Forma Earnings Per Share Diluted BusinessAcquisitionProFormaEarningsPerShareDiluted	1.64
CY2012	us-gaap	Interest Expense InterestExpense	43000000
CY2012	us-gaap	Business Acquisition Equity Interests Issued Or Issuable Number Of Shares Issued BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued	5966000	shares
CY2012	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	14000000
CY2012	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	9400000
CY2012	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	82300000
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.040	pure
CY2012	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	85900000
CY2012	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-14600000
CY2012	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	46	Acquisition
CY2012	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	343000000
CY2012	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	1700000
CY2012	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	-11800000
CY2012	us-gaap	Cost Of Revenue CostOfRevenue	111600000
CY2012	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.61
CY2012	us-gaap	Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	-7200000
CY2012	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.038	pure
CY2012	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	50000000
CY2012	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	2275000000
CY2012	ajg	Acquired Property Through Lease Area AcquiredPropertyThroughLeaseArea	306000	sqft
CY2012	ajg	Operating Lease Commitment Expiration Date OperatingLeaseCommitmentExpirationDate	2018-02-28
CY2012	ajg	Maximum Period For Exercise Of Stock Options MaximumPeriodForExerciseOfStockOptions	7	Y
CY2012	ajg	Number Of Years Options Expire NumberOfYearsOptionsExpire	7	Y
CY2012	ajg	Number Of Countries In Which Company Does Business Through Network Of Correspondent Brokers And Consultants NumberOfCountriesInWhichCompanyDoesBusinessThroughNetworkOfCorrespondentBrokersAndConsultants	140	Country
CY2012	ajg	Number Of Countries In Which Company Has Operations NumberOfCountriesInWhichCompanyHasOperations	18	Country
CY2012	ajg	Ultimate Award Value Multiples Of Original Value Of Units Maximum UltimateAwardValueMultiplesOfOriginalValueOfUnitsMaximum	1.5	Times
CY2012	ajg	Ultimate Award Value Multiples Of Original Value Of Units Minimum UltimateAwardValueMultiplesOfOriginalValueOfUnitsMinimum	0.5	Times
CY2012	ajg	Fee Revenue Generation Period Years FeeRevenueGenerationPeriodYears	1	Y
CY2012	ajg	Supplemental Commissions SupplementalCommissions	67900000
CY2012	ajg	Tax Expense From Issuance Of Common Stock TaxExpenseFromIssuanceOfCommonStock	500000
CY2012	ajg	Tax Impact From Issuance Of Common Stock TaxImpactFromIssuanceOfCommonStock	500000
CY2012	ajg	Unearned Deferred Compensation Value UnearnedDeferredCompensationValue	5600000
CY2012	ajg	Recorded Earn Out Payable RecordedEarnOutPayable	87600000
CY2012	ajg	Revenues From Clean Coal Activities RevenuesFromCleanCoalActivities	119600000
CY2012	ajg	Net Proceeds From Sales Of Operations NetProceedsFromSalesOfOperations	11400000
CY2012	ajg	Net Proceeds Of Investment Transactions NetProceedsOfInvestmentTransactions	1500000
CY2012	ajg	Net Change In Accrued Compensation And Other Accrued Liabilities NetChangeInAccruedCompensationAndOtherAccruedLiabilities	-19200000
CY2012	ajg	Goodwill Earnout Adjustments GoodwillEarnoutAdjustments	-100000
CY2012	ajg	Cash Based Compensation Award Expenses CashBasedCompensationAwardExpenses	7500000
CY2012	ajg	Change In Estimated Acquisition Earnout Payables ChangeInEstimatedAcquisitionEarnoutPayables	3400000
CY2012	ajg	Cash And Equity Award With Aggregate Fair Value Vested And Distributed To Participants CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants	700000
CY2012	ajg	Business Combination Aggregate Earnout Obligation Maximum BusinessCombinationAggregateEarnoutObligationMaximum	384800000
CY2012	ajg	Net Change In Fees Receivable Unearned Fees NetChangeInFeesReceivableUnearnedFees	-4300000
CY2012	ajg	Income Tax Reconciliation Changes In Unrecognized Tax Benefits Related To Resolution Of Federal And State Audits Expiration Of Various Statutes Of Limitations And Other Items IncomeTaxReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems	600000
CY2012	ajg	Income Tax Reconciliation Foreign Dividends And Other Permanent Differences IncomeTaxReconciliationForeignDividendsAndOtherPermanentDifferences	-2700000
CY2012	ajg	Fair Value Of Funded Cash Award Assets FairValueOfFundedCashAwardAssets	41600000
CY2012	ajg	Business Combination Aggregate Earnout Obligation Recorded Maximum BusinessCombinationAggregateEarnoutObligationRecordedMaximum	139800000
CY2012	ajg	Business Combination Annualize Revenue BusinessCombinationAnnualizeRevenue	231700000
CY2012	ajg	Commissions Commissions	1302500000
CY2012	ajg	Allowances For Estimated Policy Cancellations AllowancesForEstimatedPolicyCancellations	4000000
CY2012	ajg	Amortization Of Deferred Compensation And Restricted Stock AmortizationOfDeferredCompensationAndRestrictedStock	8300000
CY2012	ajg	Deferred Compensation And Restricted Stock DeferredCompensationAndRestrictedStock	8000000
CY2012	ajg	Contingent Commissions ContingentCommissions	42900000
CY2012	ajg	Defined Benefit Plan Discretionary Contributions By Employer DefinedBenefitPlanDiscretionaryContributionsByEmployer	7200000
CY2012	ajg	Minimum Exercise Price Of Stock Options Percent Of Fair Market Value Of Share Of Common Stock On Date Of Grant MinimumExercisePriceOfStockOptionsPercentOfFairMarketValueOfShareOfCommonStockOnDateOfGrant	1.00	pure
CY2012	ajg	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return On Plan Assets DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnPlanAssets	0.0750	pure
CY2012	ajg	Effective Income Tax Rate Reconciliation Changes In Unrecognized Tax Benefits Related To Resolution Of Federal And State Audits Expiration Of Various Statutes Of Limitations And Other Items EffectiveIncomeTaxRateReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems	0.002	pure
CY2012	ajg	Effective Income Tax Rate Reconciliation Foreign Dividends And Other Permanent Differences EffectiveIncomeTaxRateReconciliationForeignDividendsAndOtherPermanentDifferences	-0.011	pure
CY2012	ajg	Acquired Property Through Lease Percentage AcquiredPropertyThroughLeasePercentage	0.60	pure
CY2012	ajg	Expected Period Of Return On Plan Assets ExpectedPeriodOfReturnOnPlanAssets	10	Y
CY2012	ajg	Number Of Financial Institutions Entered In Unsecured Multicurrency Credit Agreement NumberOfFinancialInstitutionsEnteredInUnsecuredMulticurrencyCreditAgreement	12	Institution
CY2012	ajg	Options To Purchase Common Stock Shares Outstanding OptionsToPurchaseCommonStockSharesOutstanding	1100000	shares
CY2012	ajg	Weighted Average Number Of Common And Common Equivalent Shares Outstanding WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding	122500000	shares
CY2012	ajg	Unearned Deferred Compensation Share UnearnedDeferredCompensationShare	610000	shares
CY2012	ajg	Deferred Equity Participation Plan Distributions To Key Executives Age DeferredEquityParticipationPlanDistributionsToKeyExecutivesAge	Age 62 or upon or after their actual retirement
CY2012	ajg	Maturity Period Of Short Term Investments MaturityPeriodOfShortTermInvestments	90 days or less
CY2012	ajg	Weighted Average Period WeightedAveragePeriod	P4Y
CY2012	ajg	Additional Equity Compensation Expenses AdditionalEquityCompensationExpenses	300000
CY2012	ajg	Earnout Obligations Of Acquisitions EarnoutObligationsOfAcquisitions	5	Acquisition
CY2011	ajg	Stock Based Compensation Stock Option Granted By Compensation Committee To Officers And Key Employers Exercisable Rate StockBasedCompensationStockOptionGrantedByCompensationCommitteeToOfficersAndKeyEmployersExercisableRate	0.20	pure
	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	248	Entity
CY2011Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2011Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2011Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2011Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	23500000
CY2011Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	15200000
CY2011Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.14
CY2011Q1	us-gaap	Net Income Loss NetIncomeLoss	15200000
CY2011Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.14
CY2011Q1	us-gaap	Revenues Revenues	447400000
CY2011Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.14
CY2011Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.14
CY2011Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	423900000
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2011Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	65900000
CY2011Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	41700000
CY2011Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.38
CY2011Q2	us-gaap	Net Income Loss NetIncomeLoss	41700000
CY2011Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.37
CY2011Q2	us-gaap	Revenues Revenues	546100000
CY2011Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.37
CY2011Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.38
CY2011Q2	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	480200000
CY2012Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2012Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2012Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2012Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	32500000
CY2012Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.50
CY2012Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	28100000
CY2012Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.24
CY2012Q1	us-gaap	Net Income Loss NetIncomeLoss	28100000
CY2012Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.24
CY2012Q1	us-gaap	Revenues Revenues	546800000
CY2012Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.24
CY2012Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.24
CY2012Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	514300000
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2012Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	91100000
CY2012Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	71700000
CY2012Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.60
CY2012Q2	us-gaap	Net Income Loss NetIncomeLoss	71700000
CY2012Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.59
CY2012Q2	us-gaap	Revenues Revenues	649900000
CY2012Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.59
CY2012Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.60
CY2012Q2	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	558800000
CY2011Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2011Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2011Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2011Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	71000000
CY2011Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	46700000
CY2011Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.41
CY2011Q3	us-gaap	Net Income Loss NetIncomeLoss	46700000
CY2011Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.41
CY2011Q3	us-gaap	Revenues Revenues	562800000
CY2011Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.41
CY2011Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.41
CY2011Q3	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	491800000
CY2012Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2012Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2012Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2012Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	76300000
CY2012Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	61700000
CY2012Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.50
CY2012Q3	us-gaap	Net Income Loss NetIncomeLoss	61700000
CY2012Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2012Q3	us-gaap	Revenues Revenues	650400000
CY2012Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.50
CY2011Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.35
CY2011Q4	us-gaap	Revenues Revenues	578400000
CY2011Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.35
CY2012Q3	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	574100000
CY2010Q4	ajg	Compensation Approved By Committee Value CompensationApprovedByCommitteeValue	5900000
CY2011Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2011Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2011Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2011Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	47400000
CY2011Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	40500000
CY2011Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.36
CY2011Q4	us-gaap	Net Income Loss NetIncomeLoss	40500000
CY2011Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.36
CY2011Q4	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	531000000
CY2011Q4	ajg	Compensation Approved By Committee Value CompensationApprovedByCommitteeValue	6500000
CY2012Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
CY2012Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
CY2012Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
CY2012Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	45400000
CY2012Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	33500000
CY2012Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.27
CY2012Q4	us-gaap	Net Income Loss NetIncomeLoss	33500000
CY2012Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.27
CY2012Q4	us-gaap	Revenues Revenues	673200000
CY2012Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.27
CY2012Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.27
CY2012Q4	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	627800000
CY2012Q4	ajg	Compensation Approved By Committee Value CompensationApprovedByCommitteeValue	7300000

Files In Submission

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2012 Q4 Form 10-K Financial Statement

#000119312513046126 Filed on February 08, 2013

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AJG Arthur J. Gallagher & Co. Stock $ajg

2012 Q4 Form 10-K Financial Statement

#000119312513046126 Filed on February 08, 2013

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AJG
Arthur J. Gallagher & Co. Stock $ajg