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

$ajg Overview Financials Valuation SEC Filings Company Website

2014 Q4 Form 10-K Financial Statement

#000119312516457703 Filed on February 10, 2016

Income Statement

Concept	2014 Q4	2014 Q3	2014 Q2
Revenue	$1.245B	$1.287B	$1.179B
YoY Change	39.9%	53.96%	51.29%
Cost Of Revenue	$897.9M	$326.2M	$270.5M
YoY Change	42.8%	122.06%	253.13%
Gross Profit	$347.5M	$960.6M	$908.8M
YoY Change	32.94%	39.44%	29.29%
Gross Profit Margin	27.9%	74.65%	77.06%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$73.60M	$18.60M	$16.60M
YoY Change	46.32%	30.07%	26.72%
% of Gross Profit	21.18%	1.94%	1.83%
Operating Expenses	$295.5M	$197.3M	$179.2M
YoY Change	49.09%	48.23%	30.04%
Operating Profit	$52.00M	$763.3M	$729.6M
YoY Change	-17.72%	37.33%	29.11%
Interest Expense	-$25.70M	$25.90M	$21.20M
YoY Change	84.89%	97.71%	78.15%
% of Operating Profit	-49.42%	3.39%	2.91%
Other Income/Expense, Net
YoY Change
Pretax Income	$30.30M	$95.40M	$111.9M
YoY Change	-38.54%	11.58%	14.89%
Income Tax	-$25.20M	-$5.900M	-$1.800M
% Of Pretax Income	-83.17%	-6.18%	-1.61%
Net Earnings	$51.50M	$93.60M	$109.0M
YoY Change	-14.17%	25.47%	16.58%
Net Earnings / Revenue	4.14%	7.27%	9.24%
Basic Earnings Per Share		$0.58	$0.71
Diluted Earnings Per Share	$313.6K	$0.58	$0.70
COMMON SHARES
Basic Shares Outstanding		160.2M shares	154.3M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2014 Q4	2014 Q3	2014 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$314.0M	$291.0M	$974.0M
YoY Change	5.37%	1.39%	305.83%
Cash & Equivalents	$314.4M	$290.5M	$973.5M
Short-Term Investments
Other Short-Term Assets	$666.7M	$670.8M	$360.2M
YoY Change	155.15%	157.5%	76.66%
Inventory
Prepaid Expenses	$72.10M
Receivables
Other Receivables
Total Short-Term Assets	$3.811B	$3.972B	$4.440B
YoY Change	32.54%	55.98%	70.61%
LONG-TERM ASSETS
Property, Plant & Equipment	$195.4M	$196.6M	$193.7M
YoY Change	21.82%	32.75%	57.48%
Goodwill	$3.450B	$3.296B	$3.028B
YoY Change	60.81%	86.07%	101.02%
Intangibles	$1.776B	$1.771B	$1.632B
YoY Change	64.63%	92.93%	107.91%
Long-Term Investments
YoY Change
Other Assets	$385.2M	$399.0M	$397.3M
YoY Change	20.11%	31.99%	46.82%
Total Long-Term Assets	$6.199B	$6.016B	$5.579B
YoY Change	55.56%	75.71%	88.51%
TOTAL ASSETS
Total Short-Term Assets	$3.811B	$3.972B	$4.440B
Total Long-Term Assets	$6.199B	$6.016B	$5.579B
Total Assets	$10.01B	$9.988B	$10.02B
YoY Change	45.91%	67.3%	80.14%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$2.623B	$2.755B	$2.819B
YoY Change	21.72%	46.86%	44.71%
Accrued Expenses	$624.0M	$561.0M	$492.0M
YoY Change	68.19%	55.4%	73.24%
Deferred Revenue
YoY Change
Short-Term Debt	$140.0M	$147.0M	$253.0M
YoY Change	-77.8%	-37.58%
Long-Term Debt Due	$140.0M	$147.0M	$253.0M
YoY Change	-77.81%	-37.71%
Total Short-Term Liabilities	$3.643B	$3.770B	$3.875B
YoY Change	10.9%	46.24%	65.34%
LONG-TERM LIABILITIES
Long-Term Debt	$2.125B	$2.125B	$2.125B
YoY Change	157.58%	157.58%	129.73%
Other Long-Term Liabilities	$937.2M	$837.2M	$769.7M
YoY Change	40.89%	31.82%	30.15%
Total Long-Term Liabilities	$3.062B	$2.962B	$2.895B
YoY Change	105.49%	102.88%	90.89%
TOTAL LIABILITIES
Total Short-Term Liabilities	$3.643B	$3.770B	$3.875B
Total Long-Term Liabilities	$3.062B	$2.962B	$2.895B
Total Liabilities	$6.705B	$6.732B	$6.770B
YoY Change	40.42%	66.72%	75.38%
SHAREHOLDERS EQUITY
Retained Earnings	$676.0M	$683.7M	$648.4M
YoY Change	13.35%	17.23%	16.85%
Common Stock	$2.814B	$2.656B	$2.547B
YoY Change	88.64%	90.97%	108.82%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$3.229B	$3.256B	$3.250B
YoY Change
Total Liabilities & Shareholders Equity	$10.01B	$9.988B	$10.02B
YoY Change	45.91%	67.3%	80.14%

Cashflow Statement

Concept	2014 Q4	2014 Q3	2014 Q2
OPERATING ACTIVITIES
Net Income	$51.50M	$93.60M	$109.0M
YoY Change	-14.17%	25.47%	16.58%
Depreciation, Depletion And Amortization	$73.60M	$18.60M	$16.60M
YoY Change	46.32%	30.07%	26.72%
Cash From Operating Activities	$144.1M	$35.40M	$138.7M
YoY Change	102.1%	-82.71%	513.72%
INVESTING ACTIVITIES
Capital Expenditures	-$21.80M	-$17.60M	-$22.30M
YoY Change	-8.4%	-48.08%	-16.17%
Acquisitions
YoY Change
Other Investing Activities	-$79.20M	-$431.7M	-$1.395B
YoY Change	-80.07%	86.64%	1216.9%
Cash From Investing Activities	-$101.0M	-$449.3M	-$1.417B
YoY Change	-76.02%	69.42%	969.36%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-33.00M	-264.3M	1.494B
YoY Change	-109.13%	-353.89%	1054.25%
NET CHANGE
Cash From Operating Activities	144.1M	35.40M	138.7M
Cash From Investing Activities	-101.0M	-449.3M	-1.417B
Cash From Financing Activities	-33.00M	-264.3M	1.494B
Net Change In Cash	10.10M	-678.2M	215.4M
YoY Change	-11.4%	-1651.95%	1004.62%
FREE CASH FLOW
Cash From Operating Activities	$144.1M	$35.40M	$138.7M
Capital Expenditures	-$21.80M	-$17.60M	-$22.30M
Free Cash Flow	$165.9M	$53.00M	$161.0M
YoY Change	74.45%	-77.8%	227.24%

Facts In Submission

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CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities	127400000
CY2015Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	1100000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Noncurrent Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities	19400000
CY2015Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	958900000
CY2015Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	245000000
CY2015Q4	us-gaap	Long Term Debt LongTermDebt	62800000
CY2015Q4	us-gaap	Deferred Rent Credit Current DeferredRentCreditCurrent	-8700000
CY2015Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	76400000
CY2015Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	15700000
CY2015Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	58600000
CY2015Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	10800000
CY2015Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	261800000
CY2015Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	11700000
CY2015Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	774500000
CY2015Q4	us-gaap	Liabilities Liabilities	7225600000
CY2015Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	10913800000
CY2015Q4	us-gaap	Common Stock Value CommonStockValue	176900000
CY2015Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	13500000
CY2015Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	-71800000
CY2015Q4	us-gaap	Assets Current AssetsCurrent	4335800000
CY2015Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3688200000
CY2015Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	54300000
CY2015Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	12500000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Liabilities Other BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther	7100000
CY2015Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	398900000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities	146800000
CY2015Q4	us-gaap	Minority Interest MinorityInterest	49900000
CY2015Q4	us-gaap	Liabilities Current LiabilitiesCurrent	4191700000
CY2015Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	12000000
CY2015Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	52800000
CY2015Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	307100000
CY2015Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-522500000
CY2015Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	231900000
CY2015Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	13100000
CY2015Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	34300000
CY2015Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	25900000
CY2015Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	22100000
CY2015Q4	us-gaap	Equity Method Investment Summarized Financial Information Assets EquityMethodInvestmentSummarizedFinancialInformationAssets	83600000
CY2015Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	21100000
CY2015Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	696300000
CY2015Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	492200000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Property Plant And Equipment BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment	8600000
CY2015Q4	us-gaap	Deferred Tax Assets Investments DeferredTaxAssetsInvestments	9500000
CY2015Q4	us-gaap	Finite Lived Trade Names Gross FiniteLivedTradeNamesGross	300000
CY2015Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	34800000
CY2015Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	36600000
CY2015Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	12600000
CY2015Q4	us-gaap	Assets Assets	10913800000
CY2015Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax	108200000
CY2015Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	208300000
CY2015Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	222300000
CY2015Q4	us-gaap	Accounts Receivable Billed For Long Term Contracts Or Programs AccountsReceivableBilledForLongTermContractsOrPrograms	220200000
CY2015Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	1698800000
CY2015Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards General Business DeferredTaxAssetsTaxCreditCarryforwardsGeneralBusiness	233400000
CY2015Q4	us-gaap	Escrow Deposit EscrowDeposit	34200000
CY2015Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	202700000
CY2015Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	232700000
CY2015Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-54300000
CY2015Q4	us-gaap	Premiums And Other Receivables Net PremiumsAndOtherReceivablesNet	1734000000
CY2015Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	643500000
CY2015Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	178100000
CY2015Q4	us-gaap	Other Assets Current OtherAssetsCurrent	709300000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Assets Other BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther	138700000
CY2015Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	291400000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet	627800000
CY2015Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	92700000
CY2015Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	7700000
CY2015Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	40100000
CY2015Q4	us-gaap	Deferred Tax Assets Liabilities Net Current DeferredTaxAssetsLiabilitiesNetCurrent	120800000
CY2015Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	1412100000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Noncurrent Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentAssets	1400000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets	774600000
CY2015Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	207500000
CY2015Q4	us-gaap	Goodwill Goodwill	3662900000
CY2015Q4	us-gaap	Prepaid Expense Current PrepaidExpenseCurrent	79100000
CY2015Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Cash And Equivalents BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents	4300000
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	480400000
CY2015Q4	us-gaap	Deferred Tax Assets Net Noncurrent DeferredTaxAssetsNetNoncurrent	521400000
CY2015Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	194800000
CY2015Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	10000000
CY2015Q4	us-gaap	Defined Benefit Plan Amounts Recognized In Balance Sheet DefinedBenefitPlanAmountsRecognizedInBalanceSheet	17500000
CY2015Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	601600000
CY2015Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	106100000
CY2015Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	228300000
CY2015Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	39400000
CY2015Q4	us-gaap	Finite Lived Noncompete Agreements Gross FiniteLivedNoncompeteAgreementsGross	3700000
CY2015Q4	ajg	Deferred Tax Assets Accrued Pension Liability DeferredTaxAssetsAccruedPensionLiability	23400000
CY2015Q4	ajg	Deferred Tax Assets Alternative Minimum Tax And Other Credit Carryforwards DeferredTaxAssetsAlternativeMinimumTaxAndOtherCreditCarryforwards	341600000
CY2015Q4	ajg	Deferred Tax Liabilities Depreciable Fixed Assets DeferredTaxLiabilitiesDepreciableFixedAssets	11700000
CY2015Q4	ajg	Premium Financing Borrowings PremiumFinancingBorrowings	137000000
CY2015Q4	ajg	Funding Commitment Two FundingCommitmentTwo	1400000
CY2015Q4	ajg	Business Acquisition Cost Of Acquired Entity Purchase Price Net BusinessAcquisitionCostOfAcquiredEntityPurchasePriceNet	627800000
CY2015Q4	ajg	Refined Coal Production Related Receivables Current RefinedCoalProductionRelatedReceivablesCurrent	108100000
CY2015Q4	ajg	Accrued Compensation And Other Accrued Liabilities AccruedCompensationAndOtherAccruedLiabilities	812700000
CY2015Q4	ajg	Semi Annual Payments Of Interest SemiAnnualPaymentsOfInterest	2457000000
CY2015Q4	ajg	Expiration Lists ExpirationLists	263000000
CY2015Q4	ajg	Deferred Tax Liabilities Investment Related Partnerships DeferredTaxLiabilitiesInvestmentRelatedPartnerships	28700000
CY2015Q4	ajg	Deferred Tax Assets Accrued And Unfunded Compensation And Employee Benefits DeferredTaxAssetsAccruedAndUnfundedCompensationAndEmployeeBenefits	197000000
CY2015Q4	ajg	Accrued Supplemental Direct Bill And Other Receivables Current AccruedSupplementalDirectBillAndOtherReceivablesCurrent	181100000
CY2015Q4	ajg	Unrecognized Deferred Tax Liability On Undistributed Earnings UnrecognizedDeferredTaxLiabilityOnUndistributedEarnings	10400000
CY2015Q4	ajg	Liabilities Recorded On Self Insurance LiabilitiesRecordedOnSelfInsurance	11800000
CY2015Q4	ajg	Premiums Payable To Insurance And Reinsurance Companies PremiumsPayableToInsuranceAndReinsuranceCompanies	2877100000
CY2015Q4	ajg	Number Of Square Feet NumberOfSquareFeet	315000	sqft
CY2015Q4	ajg	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValue	36700000
CY2015Q4	ajg	Real Estate Entities Investment Carrying Value RealEstateEntitiesInvestmentCarryingValue	0
CY2015Q4	ajg	Business Acquisitions Purchase Price Allocation Goodwill Amount BusinessAcquisitionsPurchasePriceAllocationGoodwillAmount	354600000
CY2015Q4	ajg	Maximum Potential Earnout Payable MaximumPotentialEarnoutPayable	202300000
CY2015Q4	ajg	Future Amortization Expense Of Fiscal Year FutureAmortizationExpenseOfFiscalYear	1036200000
CY2015Q4	ajg	Computer Equipment Gross ComputerEquipmentGross	143400000
CY2015Q4	ajg	Number Of Real Estate Entities Investment NumberOfRealEstateEntitiesInvestment	2	Investment
CY2015Q4	ajg	Unearned Fees UnearnedFees	61300000
CY2015Q4	ajg	Equity Method Investment Summarized Financial Information Funding Commitments EquityMethodInvestmentSummarizedFinancialInformationFundingCommitments	5100000
CY2015Q3	us-gaap	Litigation Settlement Amount LitigationSettlementAmount	20000000
CY2015Q3	us-gaap	Litigation Settlement Amount LitigationSettlementAmount	31000000
CY2015Q3	ajg	Amount Received From Former Executives To Repay Loans And Retention Awards AmountReceivedFromFormerExecutivesToRepayLoansAndRetentionAwards	2000000
CY2015Q3	ajg	Amount Received From Former Executives To Repay Loans And Retention Awards AmountReceivedFromFormerExecutivesToRepayLoansAndRetentionAwards	3100000
CY2015Q4	ajg	Deferred Tax Liabilities Other Prepaid Items DeferredTaxLiabilitiesOtherPrepaidItems	4600000
CY2015Q4	ajg	Funding Commitment One FundingCommitmentOne	1500000
CY2015Q4	ajg	Number Of Certified Low Income Housing Developments Investment NumberOfCertifiedLowIncomeHousingDevelopmentsInvestment	12	Investment
CY2014Q3	us-gaap	Defined Contribution Plan Number Of Employees Covered DefinedContributionPlanNumberOfEmployeesCovered	2500	Employees
CY2013	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.06
CY2013	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	372500000
CY2013	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.016	pure
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.322	pure
CY2013	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	369975	shares
CY2013	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	79	Entity
CY2013	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.012	pure
CY2013	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	100000	shares
CY2013	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0400	pure
CY2013	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y7M13D
CY2013	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y1M24D
CY2013	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	26.01
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.005	pure
CY2013	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2013	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.296	pure
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.002	pure
CY2013	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.022	pure
CY2013	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.035	pure
CY2013	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	39.17
CY2013	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.40
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	-0.007	pure
CY2013	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0750	pure
CY2013	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1600000	shares
CY2013	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	27.11
CY2013	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	128900000	shares
CY2013	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	2300000	shares
CY2013	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.08
CY2013	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.022	pure
CY2013	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	1700000	shares
CY2013	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P3Y7M2D
CY2013	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	93600000
CY2013	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	93800000
CY2013	us-gaap	Net Income Loss NetIncomeLoss	268600000
CY2013	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	17000000
CY2013	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	10200000
CY2013	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	61800000
CY2013	us-gaap	Revenues Revenues	3179600000
CY2013	us-gaap	Payments For Proceeds From Investments PaymentsForProceedsFromInvestments	35900000
CY2013	us-gaap	Interest Paid InterestPaid	49200000
CY2013	us-gaap	Gain Loss On Investments GainLossOnInvestments	17100000
CY2013	us-gaap	Profit Loss ProfitLoss	284600000
CY2013	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	182600000
CY2013	us-gaap	Premiums Earned Net PremiumsEarnedNet	0
CY2013	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	727700000
CY2013	us-gaap	Gain Loss On Sale Of Equity Investments GainLossOnSaleOfEquityInvestments	5200000
CY2013	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	1059500000
CY2013	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	10200000
CY2013	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	57400000
CY2013	us-gaap	Income Taxes Paid IncomeTaxesPaid	49200000
CY2013	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	1800000
CY2013	us-gaap	Gain Loss On Foreign Currency Fair Value Hedge Derivatives GainLossOnForeignCurrencyFairValueHedgeDerivatives	2600000
CY2013	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	36000000
CY2013	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-7900000
CY2013	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	1600000
CY2013	us-gaap	Investment Income Net InvestmentIncomeNet	8100000
CY2013	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	85400000
CY2013	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	200000
CY2013	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	232200000
CY2013	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	53800000
CY2013	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	58600000
CY2013	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	7700000
CY2013	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	261800000
CY2013	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	4300000
CY2013	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	22600000
CY2013	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	291000000
CY2013	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	7900000
CY2013	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	291000000
CY2013	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	11700000
CY2013	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	245100000
CY2013	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	45900000
CY2013	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	11800000
CY2013	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	17900000
CY2013	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	22600000
CY2013	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	11500000
CY2013	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	298800000
CY2013	us-gaap	Premiums Written Net PremiumsWrittenNet	0
CY2013	us-gaap	Foreign Currency Transaction Gain Before Tax ForeignCurrencyTransactionGainBeforeTax	-9500000
CY2013	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	200000
CY2013	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	489000000
CY2013	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6400000
CY2013	us-gaap	Share Based Compensation ShareBasedCompensation	7700000
CY2013	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-47700000
CY2013	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-600000
CY2013	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-2000000
CY2013	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	-43900000
CY2013	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	29000000
CY2013	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	10000000
CY2013	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1600000
CY2013	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	91300000
CY2013	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-4000000
CY2013	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-13900000
CY2013	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	178600000
CY2013	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	500000
CY2013	us-gaap	Operating Expenses OperatingExpenses	535900000
CY2013	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	900000
CY2013	us-gaap	Dividends Dividends	21900000
CY2013	us-gaap	Interest Expense InterestExpense	50100000
CY2013	us-gaap	Interest Expense Domestic Deposits InterestExpenseDomesticDeposits	16600000
CY2013	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-851700000
CY2013	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-26800000
CY2013	us-gaap	Costs And Expenses CostsAndExpenses	2888600000
CY2013	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	480000000
CY2013	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	37000000
CY2013	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	76200000
CY2013	us-gaap	Cost Of Coal Products And Services CostOfCoalProductsAndServices	437300000
CY2013	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	10600000
CY2013	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-4700000
CY2013	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationBeforeTax	-40700000
CY2013	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	200000000
CY2013	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	1300000
CY2013	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	890500000
CY2013	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	600000
CY2013	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	4300000
CY2013	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	-4800000
CY2013	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	29000000
CY2013	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	101900000
CY2013	us-gaap	Labor And Related Expense LaborAndRelatedExpense	1685000000
CY2013	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	7900000
CY2013	us-gaap	Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Cost Expensed BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed	11900000
CY2013	us-gaap	Defined Benefit Plan Amount To Be Amortized From Accumulated Other Comprehensive Income Loss Next Fiscal Year DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear	2400000
CY2013	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	114300000
CY2013	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	182600000
CY2013	us-gaap	Adjustment For Amortization AdjustmentForAmortization	125200000
CY2013	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	3200000
CY2013	us-gaap	Interest Expense Foreign Deposits InterestExpenseForeignDeposits	16600000
CY2013	us-gaap	Depreciation Depreciation	53400000
CY2013	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	-18700000
CY2013	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	15100000
CY2013	us-gaap	Income Loss Attributable To Noncontrolling Interest IncomeLossAttributableToNoncontrollingInterest	16000000
CY2013	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	2200000
CY2013	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	16000000
CY2013	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Reclassification Adjustment From Aoci Realized Upon Sale Or Liquidation Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationBeforeTax	0
CY2013	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	6500000
CY2013	ajg	Amortization Of Deferred Compensation And Restricted Stock AmortizationOfDeferredCompensationAndRestrictedStock	19000000
CY2013	ajg	Income Tax Reconciliation Other Permanent Differences IncomeTaxReconciliationOtherPermanentDifferences	-1900000
CY2013	ajg	Number Of Periods Options Expire NumberOfPeriodsOptionsExpire	P7Y
CY2013	ajg	Revenues From Clean Coal Activities RevenuesFromCleanCoalActivities	412500000
CY2013	ajg	Net Change In Fees Receivable Unearned Fees NetChangeInFeesReceivableUnearnedFees	5900000
CY2013	ajg	Net Change In Accrued Compensation And Other Accrued Liabilities NetChangeInAccruedCompensationAndOtherAccruedLiabilities	-42700000
CY2013	ajg	Change In Estimated Acquisition Earnout Payables ChangeInEstimatedAcquisitionEarnoutPayables	1700000
CY2013	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	1500000
CY2013	ajg	Contingent Commissions ContingentCommissions	52100000
CY2013	ajg	Tax Impact From Issuance Of Common Stock TaxImpactFromIssuanceOfCommonStock	7500000
CY2013	ajg	Commissions Commissions	1553100000
CY2013	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	0.005	pure
CY2013	ajg	Weighted Average Number Of Common And Common Equivalent Shares Outstanding WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding	130500000	shares
CY2013	ajg	Net Proceeds From Sales Of Operations NetProceedsFromSalesOfOperations	5500000
CY2013	ajg	Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue	32000000
CY2013	ajg	Effective Income Tax Rate Reconciliation Other Permanent Differences EffectiveIncomeTaxRateReconciliationOtherPermanentDifferences	-0.007	pure
CY2013	ajg	Defined Benefit Plan Discretionary Contributions By Employer DefinedBenefitPlanDiscretionaryContributionsByEmployer	6300000
CY2013	ajg	Deferred Compensation And Restricted Stock DeferredCompensationAndRestrictedStock	-13000000
CY2013	ajg	Defined Benefit Plan Minimum Contribution By Employer DefinedBenefitPlanMinimumContributionByEmployer	0
CY2013	ajg	Tax Expense From Issuance Of Common Stock TaxExpenseFromIssuanceOfCommonStock	7500000
CY2013	ajg	Options To Purchase Common Stock Shares Outstanding OptionsToPurchaseCommonStockSharesOutstanding	1300000	shares
CY2013	ajg	Supplemental Commissions SupplementalCommissions	77300000
CY2014	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.97
CY2014	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	436600000
CY2014	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y6M
CY2014	us-gaap	Business Acquisition Pro Forma Earnings Per Share Diluted BusinessAcquisitionProFormaEarningsPerShareDiluted	1.97
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.038	pure
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.499	pure
CY2014	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	376541	shares
CY2014	us-gaap	Business Acquisition Pro Forma Earnings Per Share Basic BusinessAcquisitionProFormaEarningsPerShareBasic	1.99
CY2014	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	67	Entity
CY2014	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.018	pure
CY2014	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	200000	shares
CY2014	us-gaap	Defined Benefit Plan Benefit Obligation Period Increase Decrease DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease	-60000000
CY2014	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0475	pure
CY2014	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y11M16D
CY2014	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P1Y10M13D
CY2014	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	28.36
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.005	pure
CY2014	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.019	pure
CY2014	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.289	pure
CY2014	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.041	pure
CY2014	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.030	pure
CY2014	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	46.86
CY2014	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.44
CY2014	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0750	pure
CY2014	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1400000	shares
CY2014	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	28.80
CY2014	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	152900000	shares
CY2014	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1600000	shares
CY2014	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.98
CY2014	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	-0.123	pure
CY2014	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	1900000	shares
CY2014	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P3Y11M5D
CY2014	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	81500000
CY2014	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	145500000
CY2014	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	-56800000
CY2014	us-gaap	Direct Premiums Earned DirectPremiumsEarned	2400000
CY2014	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	288100000
CY2014	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	3400000
CY2014	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	4858700000
CY2014	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	200000
CY2014	us-gaap	Net Income Loss NetIncomeLoss	303400000
CY2014	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	18700000
CY2014	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	3000000
CY2014	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	44200000
CY2014	us-gaap	Revenues Revenues	4626500000
CY2014	us-gaap	Payments For Proceeds From Investments PaymentsForProceedsFromInvestments	20100000
CY2014	us-gaap	Interest Paid InterestPaid	82500000
CY2014	us-gaap	Gain Loss On Investments GainLossOnInvestments	23000000
CY2014	us-gaap	Profit Loss ProfitLoss	327500000
CY2014	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	223100000
CY2014	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	911400000
CY2014	us-gaap	Premiums Earned Net PremiumsEarnedNet	0
CY2014	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	1918300000
CY2014	us-gaap	Gain Loss On Sale Of Equity Investments GainLossOnSaleOfEquityInvestments	7300000
CY2014	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	1258300000
CY2014	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	12400000
CY2014	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	150500000
CY2014	us-gaap	Income Taxes Paid IncomeTaxesPaid	72900000
CY2014	us-gaap	Defined Benefit Plan Recognized Net Gain Loss Due To Settlements1 DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1	-12000000
CY2014	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-1000000
CY2014	us-gaap	Gain Loss On Foreign Currency Fair Value Hedge Derivatives GainLossOnForeignCurrencyFairValueHedgeDerivatives	1900000
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-42500000
CY2014	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-2300000
CY2014	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Loss Net Gain Loss Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax	12000000
CY2014	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	-238400000
CY2014	us-gaap	Investment Income Net InvestmentIncomeNet	41300000
CY2014	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-95300000
CY2014	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	500000
CY2014	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	2300000
CY2014	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	299300000
CY2014	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	126100000
CY2014	us-gaap	Direct Premiums Written DirectPremiumsWritten	34900000
CY2014	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	62100000
CY2014	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	9500000
CY2014	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	13900000
CY2014	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	29000000
CY2014	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-231000000
CY2014	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1700000
CY2014	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	291500000
CY2014	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	2300000
CY2014	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2600000
CY2014	us-gaap	Premiums Written Net PremiumsWrittenNet	0
CY2014	us-gaap	Foreign Currency Transaction Gain Before Tax ForeignCurrencyTransactionGainBeforeTax	141500000
CY2014	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	500000
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	12400000
CY2014	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	34300000
CY2014	us-gaap	Goodwill Written Off Related To Sale Of Business Unit GoodwillWrittenOffRelatedToSaleOfBusinessUnit	600000
CY2014	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	22900000
CY2014	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	45400000
CY2014	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	18400000
CY2014	us-gaap	Defined Benefit Plan Other Changes DefinedBenefitPlanOtherChanges	17000000
CY2014	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	1500400000
CY2014	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	291500000
CY2014	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	12700000
CY2014	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-36000000
CY2014	us-gaap	Share Based Compensation ShareBasedCompensation	10600000
CY2014	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	-8800000
CY2014	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-96600000
CY2014	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-1100000
CY2014	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	28200000
CY2014	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0
CY2014	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	30500000
CY2014	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	18400000
CY2014	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	1400000
CY2014	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	122000000
CY2014	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	16300000
CY2014	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-27100000
CY2014	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	258900000
CY2014	us-gaap	Operating Expenses OperatingExpenses	743100000
CY2014	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	600000
CY2014	us-gaap	Dividends Dividends	34400000
CY2014	us-gaap	Interest Expense InterestExpense	89000000
CY2014	us-gaap	Interest Expense Domestic Deposits InterestExpenseDomesticDeposits	76500000
CY2014	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-2011700000
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	18600000
CY2014	us-gaap	Costs And Expenses CostsAndExpenses	4335000000
CY2014	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	1563500000
CY2014	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	31500000
CY2014	us-gaap	Proceeds From Issuance Of Debt ProceedsFromIssuanceOfDebt	7500000
CY2014	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	997000000
CY2014	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	0
CY2014	us-gaap	Ceded Premiums Written CededPremiumsWritten	37200000
CY2014	us-gaap	Cost Of Coal Products And Services CostOfCoalProductsAndServices	1058900000
CY2014	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	19500000
CY2014	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	54000000
CY2014	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-11200000
CY2014	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationBeforeTax	37200000
CY2014	us-gaap	Ceded Premiums Earned CededPremiumsEarned	2600000
CY2014	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	-134500000
CY2014	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-700000
CY2014	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1200000000
CY2014	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	5400000
CY2014	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	1109900000
CY2014	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	700000
CY2014	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	4900000
CY2014	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	27900000
CY2014	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	38800000
CY2014	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	102000000
CY2014	us-gaap	Labor And Related Expense LaborAndRelatedExpense	2167600000
CY2014	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	14300000
CY2014	us-gaap	Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Cost Expensed BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed	14500000
CY2014	us-gaap	Defined Benefit Plan Amount To Be Amortized From Accumulated Other Comprehensive Income Loss Next Fiscal Year DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear	6000000
CY2014	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	60000000
CY2014	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	223800000
CY2014	us-gaap	Adjustment For Amortization AdjustmentForAmortization	189500000
CY2014	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	9000000
CY2014	us-gaap	Interest Expense Foreign Deposits InterestExpenseForeignDeposits	76500000
CY2014	us-gaap	Defined Benefit Plan Settlements Benefit Obligation DefinedBenefitPlanSettlementsBenefitObligation	16700000
CY2014	us-gaap	Depreciation Depreciation	69400000
CY2014	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	-57800000
CY2014	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	3400000
CY2014	us-gaap	Income Loss Attributable To Noncontrolling Interest IncomeLossAttributableToNoncontrollingInterest	24100000
CY2014	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	1000000
CY2014	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	16300000
CY2014	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	1800000
CY2014	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	24100000
CY2014	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Reclassification Adjustment From Aoci Realized Upon Sale Or Liquidation Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationBeforeTax	0
CY2014	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	1448300000
CY2014	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	12000000
CY2014	ajg	Amortization Of Deferred Compensation And Restricted Stock AmortizationOfDeferredCompensationAndRestrictedStock	22900000
CY2014	ajg	Business Acquisitions Pro Forma Net Income Loss To Controlling Interest BusinessAcquisitionsProFormaNetIncomeLossToControllingInterest	316500000
CY2014	ajg	Income Tax Reconciliation Other Permanent Differences IncomeTaxReconciliationOtherPermanentDifferences	-2500000
CY2014	ajg	Business Combination Aggregate Earnout Obligation Maximum BusinessCombinationAggregateEarnoutObligationMaximum	549800000
CY2014	ajg	Number Of Periods Options Expire NumberOfPeriodsOptionsExpire	P7Y
CY2014	ajg	Revenues From Clean Coal Activities RevenuesFromCleanCoalActivities	1029500000
CY2014	ajg	Net Change In Fees Receivable Unearned Fees NetChangeInFeesReceivableUnearnedFees	26000000
CY2014	ajg	Net Change In Accrued Compensation And Other Accrued Liabilities NetChangeInAccruedCompensationAndOtherAccruedLiabilities	-191600000
CY2014	ajg	Change In Estimated Acquisition Earnout Payables ChangeInEstimatedAcquisitionEarnoutPayables	17500000
CY2014	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	2400000
CY2014	ajg	Contingent Commissions ContingentCommissions	84700000
CY2014	ajg	Tax Impact From Issuance Of Common Stock TaxImpactFromIssuanceOfCommonStock	6900000
CY2014	ajg	Commissions Commissions	2083000000
CY2014	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	0.008	pure
CY2014	ajg	Weighted Average Number Of Common And Common Equivalent Shares Outstanding WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding	154300000	shares
CY2014	ajg	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return On Plan Assets DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnPlanAssets	0.0750	pure
CY2014	ajg	Expected Period Of Return On Plan Assets ExpectedPeriodOfReturnOnPlanAssets	P10Y
CY2014	ajg	Allowances For Estimated Policy Cancellations AllowancesForEstimatedPolicyCancellations	6800000
CY2014	ajg	Net Proceeds From Sales Of Operations NetProceedsFromSalesOfOperations	8200000
CY2014	ajg	Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue	30500000
CY2014	ajg	Effective Income Tax Rate Reconciliation Other Permanent Differences EffectiveIncomeTaxRateReconciliationOtherPermanentDifferences	-0.009	pure
CY2014	ajg	Business Combination Aggregate Earnout Obligation Recorded Maximum BusinessCombinationAggregateEarnoutObligationRecordedMaximum	205300000
CY2014	ajg	Additional Equity Compensation Expenses AdditionalEquityCompensationExpenses	1100000
CY2014	ajg	Defined Benefit Plan Discretionary Contributions By Employer DefinedBenefitPlanDiscretionaryContributionsByEmployer	0
CY2014	ajg	Deferred Compensation And Restricted Stock DeferredCompensationAndRestrictedStock	8500000
CY2014	ajg	Defined Benefit Plan Minimum Contribution By Employer DefinedBenefitPlanMinimumContributionByEmployer	0
CY2014	ajg	Tax Expense From Issuance Of Common Stock TaxExpenseFromIssuanceOfCommonStock	6900000
CY2014	ajg	Options To Purchase Common Stock Shares Outstanding OptionsToPurchaseCommonStockSharesOutstanding	1600000	shares
CY2014	ajg	Supplemental Commissions SupplementalCommissions	104000000
CY2014	ajg	Purchase Of Subsidiary Shares From Noncontrolling Interest PurchaseOfSubsidiarySharesFromNoncontrollingInterest	49300000
CY2015	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2015	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.06
CY2015	us-gaap	Nature Of Operations NatureOfOperations	<div> <p style="MARGIN-BOTTOM: 0px; MARGIN-TOP: 12px"><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, us or the company, provide insurance brokerage and risk management services to a wide variety of commercial, industrial, institutional and governmental organizations through three 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 are generated from our premium financing operations and our investment portfolio, which includes invested cash and restricted funds, as well as clean energy and other investments. We are headquartered in Itasca, Illinois, have operations in 31 countries and offer client-service capabilities in more than 150 countries globally through a network of correspondent insurance brokers and consultants.</font></p> </div>
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	652600000
CY2015	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y6M
CY2015	us-gaap	Business Acquisition Pro Forma Earnings Per Share Diluted BusinessAcquisitionProFormaEarningsPerShareDiluted	2.09
CY2015	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Upper Range Limit ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit	47.92
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.077	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.618	pure
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	394975	shares
CY2015	us-gaap	Business Acquisition Pro Forma Earnings Per Share Basic BusinessAcquisitionProFormaEarningsPerShareBasic	2.10
CY2015	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2015
CY2015	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	105	Entity
CY2015	dei	Amendment Flag AmendmentFlag	false
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.018	pure
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	100000	shares
CY2015	us-gaap	Basis Of Accounting BasisOfAccounting	<div> <p style="MARGIN-BOTTOM: 0px; MARGIN-TOP: 12px"><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-BOTTOM: 0px; MARGIN-TOP: 12px"><font style="FONT-FAMILY: Times New Roman" size="2">In the preparation of our consolidated financial statements as of December 31, 2015, 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>
CY2015	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0400	pure
CY2015	dei	Document Type DocumentType	10-K
CY2015	dei	Entity Central Index Key EntityCentralIndexKey	0000354190
CY2015	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y1M28D
CY2015	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P1Y11M1D
CY2015	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Lower Range Limit ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit	21.28
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.001	pure
CY2015	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2015	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.282	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.006	pure
CY2015	us-gaap	Variable Interest Entity Ownership Percentage VariableInterestEntityOwnershipPercentage	0.50	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.035	pure
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.030	pure
CY2015	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	46.19
CY2015	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.48
CY2015	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	-0.014	pure
CY2015	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2015	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0725	pure
CY2015	dei	Entity Registrant Name EntityRegistrantName	GALLAGHER ARTHUR J & CO
CY2015	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Maximum Number Of Shares Per Employee ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee	200000	shares
CY2015	us-gaap	Description Of Defined Contribution Pension And Other Postretirement Plans DescriptionOfDefinedContributionPensionAndOtherPostretirementPlans	Eligible participants had from September 12, 2014 to November 30, 2014 to accept the offer, and the lump-sum payments were made in November and December of 2014, and the accelerated reduced annuity payments began as of December 1, 2014.
CY2015	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1000000	shares
CY2015	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2015	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div> <p style="MARGIN-BOTTOM: 0px; MARGIN-TOP: 12px"><font style="FONT-FAMILY: Times New Roman" size="2"><b>Reclassification -</b> In first quarter 2015, we transferred management of a claims handling operation from the brokerage segment to the risk management segment. We made the applicable segment reclassifications to the prior-period amounts to conform to the current period presentation. The changes in the segment structure affect only the manner in which the results for the reportable segments were previously reported. These reclassifications did not impact our previously reported consolidated net earnings or financial position.</font></p> </div>
CY2015	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	27.59
CY2015	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	172200000	shares
CY2015	us-gaap	Business Acquisition Equity Interests Issued Or Issuable Number Of Shares Issued BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued	6350000	shares
CY2015	dei	Document Period End Date DocumentPeriodEndDate	2015-12-31
CY2015	us-gaap	Use Of Estimates UseOfEstimates	<div> <p style="MARGIN-BOTTOM: 0px; MARGIN-TOP: 12px"><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>
CY2015	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1400000	shares
CY2015	dei	Trading Symbol TradingSymbol	AJG
CY2015	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.07
CY2015	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	-0.326	pure
CY2015	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	Segment
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	1900000	shares
CY2015	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P4Y1M17D
CY2015	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	99000000
CY2015	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	181300000
CY2015	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	10400000
CY2015	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	5100000
CY2015	us-gaap	Net Income Loss NetIncomeLoss	356800000
CY2015	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	15300000
CY2015	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	24400000
CY2015	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	40400000
CY2015	us-gaap	Revenues Revenues	5392400000
CY2015	us-gaap	Payments For Proceeds From Investments PaymentsForProceedsFromInvestments	29500000
CY2015	us-gaap	Interest Paid InterestPaid	103900000
CY2015	us-gaap	Gain Loss On Investments GainLossOnInvestments	6600000
CY2015	us-gaap	Profit Loss ProfitLoss	389100000
CY2015	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	257500000
CY2015	us-gaap	Premiums Earned Net PremiumsEarnedNet	0
CY2015	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	342300000
CY2015	us-gaap	Gain Loss Related To Litigation Settlement GainLossRelatedToLitigationSettlement	31000000
CY2015	us-gaap	Gain Loss On Sale Of Equity Investments GainLossOnSaleOfEquityInvestments	6700000
CY2015	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	1432300000
CY2015	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	13800000
CY2015	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	34700000
CY2015	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	209300000
CY2015	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	200000
CY2015	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	4400000
CY2015	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	346200000
CY2015	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	161200000
CY2015	us-gaap	Direct Premiums Written DirectPremiumsWritten	71500000
CY2015	us-gaap	Income Taxes Paid IncomeTaxesPaid	78300000
CY2015	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-2100000
CY2015	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	249500000
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-2900000
CY2015	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-6200000
CY2015	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	-261100000
CY2015	us-gaap	Investment Income Net InvestmentIncomeNet	54200000
CY2015	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	45600000
CY2015	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	11200000
CY2015	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	69000000
CY2015	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	149200000
CY2015	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-267500000
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2100000
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	293500000
CY2015	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	6200000
CY2015	us-gaap	Direct Premiums Earned DirectPremiumsEarned	71700000
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	345600000
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-52100000
CY2015	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	5510700000
CY2015	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	30500000
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	900000
CY2015	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	39900000
CY2015	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	89500000
CY2015	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	94900000
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2900000
CY2015	us-gaap	Premiums Written Net PremiumsWrittenNet	0
CY2015	us-gaap	Foreign Currency Transaction Gain Before Tax ForeignCurrencyTransactionGainBeforeTax	154400000
CY2015	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	200000
CY2015	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	794000000
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	293500000
CY2015	us-gaap	Business Combination Consideration Transferred Equity Interests Issued And Issuable BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable	279400000
CY2015	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	10800000
CY2015	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-95600000
CY2015	us-gaap	Share Based Compensation ShareBasedCompensation	11200000
CY2015	us-gaap	Goodwill Transfers GoodwillTransfers	0
CY2015	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-38600000
CY2015	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	334200000
CY2015	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	25300000
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	500000
CY2015	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-139400000
CY2015	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-3300000
CY2015	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-4200000
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	-3300000
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0
CY2015	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	22900000
CY2015	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	15600000
CY2015	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-200000
CY2015	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	121600000
CY2015	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	166000000
CY2015	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	1700000
CY2015	us-gaap	Operating Expenses OperatingExpenses	840700000
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	0
CY2015	us-gaap	Dividends Dividends	36700000
CY2015	us-gaap	Interest Expense InterestExpense	103000000
CY2015	us-gaap	Interest Expense Domestic Deposits InterestExpenseDomesticDeposits	107000000
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-461600000
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-1300000
CY2015	us-gaap	Costs And Expenses CostsAndExpenses	5098900000
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	-9900000
CY2015	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	25900000
CY2015	us-gaap	Proceeds From Issuance Of Debt ProceedsFromIssuanceOfDebt	23900000
CY2015	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	203300000
CY2015	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	0
CY2015	us-gaap	Ceded Premiums Written CededPremiumsWritten	75900000
CY2015	us-gaap	Cost Of Coal Products And Services CostOfCoalProductsAndServices	1351500000
CY2015	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	18900000
CY2015	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	11700000
CY2015	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-22600000
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationBeforeTax	-500000
CY2015	us-gaap	Ceded Premiums Earned CededPremiumsEarned	76800000
CY2015	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	109000000
CY2015	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	-166600000
CY2015	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-1400000
CY2015	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	849000000
CY2015	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	1100000
CY2015	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-18500000
CY2015	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	-15100000
CY2015	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	43900000
CY2015	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	102700000
CY2015	us-gaap	Labor And Related Expense LaborAndRelatedExpense	2428900000
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	6200000
CY2015	us-gaap	Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Cost Expensed BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed	16200000
CY2015	us-gaap	Defined Benefit Plan Amount To Be Amortized From Accumulated Other Comprehensive Income Loss Next Fiscal Year DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear	5900000
CY2015	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	406600000
CY2015	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	258300000
CY2015	us-gaap	Adjustment For Amortization AdjustmentForAmortization	240300000
CY2015	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	2800000
CY2015	us-gaap	Interest Expense Foreign Deposits InterestExpenseForeignDeposits	107000000
CY2015	us-gaap	Depreciation Depreciation	93900000
CY2015	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	-95500000
CY2015	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	-15700000
CY2015	us-gaap	Income Loss Attributable To Noncontrolling Interest IncomeLossAttributableToNoncontrollingInterest	32300000
CY2015	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	1300000
CY2015	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	2000000
CY2015	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	11500000
CY2015	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	32300000
CY2015	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Reclassification Adjustment From Aoci Realized Upon Sale Or Liquidation Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationBeforeTax	0
CY2015	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	354600000
CY2015	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	10200000
CY2015	ajg	Number Of Countries In Which Company Has Operations NumberOfCountriesInWhichCompanyHasOperations	31	Country
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments Within Year Five AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFive	400000
CY2015	ajg	Amortization Of Deferred Compensation And Restricted Stock AmortizationOfDeferredCompensationAndRestrictedStock	22700000
CY2015	ajg	Business Acquisitions Pro Forma Net Income Loss To Controlling Interest BusinessAcquisitionsProFormaNetIncomeLossToControllingInterest	367800000
CY2015	ajg	Number Of Employees NumberOfEmployees	1750	Employees
CY2015	ajg	Income Tax Reconciliation Other Permanent Differences IncomeTaxReconciliationOtherPermanentDifferences	-4900000
CY2015	ajg	Business Combination Aggregate Earnout Obligation Maximum BusinessCombinationAggregateEarnoutObligationMaximum	565400000
CY2015	ajg	Number Of Periods Options Expire NumberOfPeriodsOptionsExpire	P7Y
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments Within Year Two AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearTwo	18200000
CY2015	ajg	Acquired Property Through Lease Area AcquiredPropertyThroughLeaseArea	306000	sqft
CY2015	ajg	Revenues From Clean Coal Activities RevenuesFromCleanCoalActivities	1310800000
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments Within Year Three AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThree	400000
CY2015	ajg	Net Change In Fees Receivable Unearned Fees NetChangeInFeesReceivableUnearnedFees	49600000
CY2015	ajg	Net Change In Accrued Compensation And Other Accrued Liabilities NetChangeInAccruedCompensationAndOtherAccruedLiabilities	-217800000
CY2015	ajg	Change In Estimated Acquisition Earnout Payables ChangeInEstimatedAcquisitionEarnoutPayables	40600000
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments Within Year Thereafter AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThereafter	25700000
CY2015	ajg	Deferred Equity Participation Plan Distributions To Key Executives Age DeferredEquityParticipationPlanDistributionsToKeyExecutivesAge	Age 62 (or the one-year anniversary of the date of the grant for participants over the age of 61 as of the grant date) or upon or after their actual retirement
CY2015	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	3000000
CY2015	ajg	Contingent Commissions ContingentCommissions	93700000
CY2015	ajg	Fee Revenue Generation Period FeeRevenueGenerationPeriod	P1Y
CY2015	ajg	Tax Impact From Issuance Of Common Stock TaxImpactFromIssuanceOfCommonStock	5300000
CY2015	ajg	Commissions Commissions	2338700000
CY2015	ajg	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return On Plan Assets DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnPlanAssets	0.0725	pure
CY2015	ajg	Weighted Average Period WeightedAveragePeriod	P4Y
CY2015	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	0.010	pure
CY2015	ajg	Weighted Average Number Of Common And Common Equivalent Shares Outstanding WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding	173200000	shares
CY2015	ajg	Number Of Clean Coal Production Plants Seeking And Negotiating For Long Term Production Contract NumberOfCleanCoalProductionPlantsSeekingAndNegotiatingForLongTermProductionContract	5	Plant
CY2015	ajg	Operating Lease Commitment Expiration Date OperatingLeaseCommitmentExpirationDate	2018-02-28
CY2015	ajg	Number Of Countries In Which Company Does Business Through Network Of Correspondent Brokers And Consultants NumberOfCountriesInWhichCompanyDoesBusinessThroughNetworkOfCorrespondentBrokersAndConsultants	150	Country
CY2015	ajg	Expected Period Of Return On Plan Assets ExpectedPeriodOfReturnOnPlanAssets	P10Y
CY2015	ajg	Maturity Period Of Short Term Investments MaturityPeriodOfShortTermInvestments	90 days or less
CY2015	ajg	Allowances For Estimated Policy Cancellations AllowancesForEstimatedPolicyCancellations	7400000
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments Within Year One AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearOne	16200000
CY2015	ajg	Net Proceeds From Sales Of Operations NetProceedsFromSalesOfOperations	9200000
CY2015	ajg	Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue	27000000
CY2015	ajg	Acquired Property Through Lease Percentage AcquiredPropertyThroughLeasePercentage	0.60	pure
CY2015	ajg	Recorded Earn Out Payable RecordedEarnOutPayable	57600000
CY2015	ajg	Effective Income Tax Rate Reconciliation Other Permanent Differences EffectiveIncomeTaxRateReconciliationOtherPermanentDifferences	-0.017	pure
CY2015	ajg	Business Combination Aggregate Earnout Obligation Recorded Maximum BusinessCombinationAggregateEarnoutObligationRecordedMaximum	229700000
CY2015	ajg	Defined Benefit Plan Discretionary Contributions By Employer DefinedBenefitPlanDiscretionaryContributionsByEmployer	0
CY2015	ajg	Deferred Compensation And Restricted Stock DeferredCompensationAndRestrictedStock	6200000
CY2015	ajg	Collateralized Delinquency Receivables Period CollateralizedDelinquencyReceivablesPeriod	P7D
CY2015	ajg	Defined Benefit Plan Minimum Contribution By Employer DefinedBenefitPlanMinimumContributionByEmployer	0
CY2015	ajg	Tax Expense From Issuance Of Common Stock TaxExpenseFromIssuanceOfCommonStock	5300000
CY2015	ajg	Options To Purchase Common Stock Shares Outstanding OptionsToPurchaseCommonStockSharesOutstanding	3500000	shares
CY2015	ajg	Supplemental Commissions SupplementalCommissions	125500000
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments Within Year Four AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFour	1900000
CY2015	ajg	Purchase Of Subsidiary Shares From Noncontrolling Interest PurchaseOfSubsidiarySharesFromNoncontrollingInterest	-15000000
CY2015	ajg	Amount Of Commitment Expiration Off Balance Sheet Commitments AmountOfCommitmentExpirationOffBalanceSheetCommitments	62800000
CY2015	ajg	Insurance Contracts Premium Financing Terms InsuranceContractsPremiumFinancingTerms	Premium financing contracts are structured to minimize potential bad debt expense to us. Such receivables are generally considered delinquent after seven days of the payment due date. In normal course, insurance policies are cancelled within one month of the contractual payment due date if the payment remains delinquent.
	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	383	Entity
CY2014Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.36
CY2014Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.37
CY2014Q1	us-gaap	Net Income Loss NetIncomeLoss	49300000
CY2014Q1	us-gaap	Revenues Revenues	915000000
CY2014Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	53900000
CY2014Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	861100000
CY2015Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.13
CY2015Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.13
CY2015Q1	us-gaap	Net Income Loss NetIncomeLoss	21900000
CY2015Q1	us-gaap	Revenues Revenues	1231300000
CY2015Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	30900000
CY2015Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1200400000
CY2014Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.70
CY2014Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.71
CY2014Q2	us-gaap	Net Income Loss NetIncomeLoss	109000000
CY2014Q2	us-gaap	Revenues Revenues	1179300000
CY2014Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	111900000
CY2014Q2	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1067400000
CY2015Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.81
CY2015Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.82
CY2015Q2	us-gaap	Net Income Loss NetIncomeLoss	139300000
CY2015Q2	us-gaap	Revenues Revenues	1371400000
CY2015Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	128500000
CY2015Q2	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1242900000
CY2014Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.58
CY2014Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.58
CY2014Q3	us-gaap	Net Income Loss NetIncomeLoss	93600000
CY2014Q3	us-gaap	Revenues Revenues	1286800000
CY2014Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	95400000
CY2014Q3	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1191400000
CY2015Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.75
CY2015Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.76
CY2015Q3	us-gaap	Net Income Loss NetIncomeLoss	133300000
CY2015Q3	us-gaap	Revenues Revenues	1454800000
CY2015Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	105700000
CY2015Q3	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1349100000
CY2014Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.31
CY2014Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.32
CY2014Q4	us-gaap	Net Income Loss NetIncomeLoss	51500000
CY2014Q4	us-gaap	Revenues Revenues	1245400000
CY2014Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	30300000
CY2014Q4	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	43300000
CY2014Q4	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1215100000
CY2014Q4	ajg	Defined Benefit Plan Settlements Benefit Obligation Before Tax DefinedBenefitPlanSettlementsBenefitObligationBeforeTax	12000000
CY2015Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.35
CY2015Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.35
CY2015Q4	us-gaap	Net Income Loss NetIncomeLoss	62300000
CY2015Q4	us-gaap	Revenues Revenues	1334900000
CY2015Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	28400000
CY2015Q4	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1306500000

Files In Submission

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2014 Q4 Form 10-K Financial Statement

#000119312516457703 Filed on February 10, 2016

Income Statement

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Facts In Submission

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

2014 Q4 Form 10-K Financial Statement

#000119312516457703 Filed on February 10, 2016

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

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