Arthur J. Gallagher & Co. (AJG) 10-K13 Feb 152014 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2014	Jan. 31, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	AJG
Entity Registrant Name	GALLAGHER ARTHUR J & CO
Entity Central Index Key	354190
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		164,744,000
Entity Public Float			$6,838,200,000

Consolidated_Statement_of_Earn

Consolidated Statement of Earnings (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Commissions	$2,083	$1,553.10	$1,302.50
Fees	1,258.30	1,059.50	971.7
Supplemental commissions	104	77.3	67.9
Contingent commissions	84.7	52.1	42.9
Investment income	41.3	8.1	10.4
Gains on books of business sales	7.3	5.2	3.9
Revenues from clean coal activities	1,029.50	412.5	119.6
Other net revenues	18.4	11.8	1.4
Total revenues	4,626.50	3,179.60	2,520.30
Compensation	2,167.60	1,685	1,493.40
Operating	767.2	552.4	483.2
Cost of revenues from clean coal activities	1,058.90	437.3	111.6
Interest	89	50.1	43
Depreciation	69.4	53.4	41.4
Amortization	189.5	125.2	99
Change in estimated acquisition earnout payables	17.5	1.7	3.4
Total expenses	4,359.10	2,905.10	2,275
Earnings before income taxes	267.4	274.5	245.3
Provision (benefit) for income taxes	-36	5.9	50.3
Net earnings	$303.40	$268.60	$195
Basic net earnings per share:	$1.98	$2.08	$1.61
Diluted net earnings per share:	$1.97	$2.06	$1.59
Dividends declared per common share	$1.44	$1.40	$1.36

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Earnings (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net earnings	$303.40	$268.60	$195
Change in pension liability, net of taxes	-18.6	26.8	-3.4
Foreign currency translation	-238.4	1.6	16.1
Change in fair value of derivative instruments, net of taxes	-1	1.8	1.7
Comprehensive earnings	$45.40	$298.80	$209.40

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Cash and cash equivalents	$314.40	$298.10
Restricted cash	1,367.60	1,027.40
Premiums and fees receivable	1,462.50	1,288.80
Other current assets	666.7	261.3
Total current assets	3,811.20	2,875.60
Fixed assets - net	195.4	160.4
Deferred income taxes	392.6	279.8
Other noncurrent assets	385.2	320.7
Goodwill - net	3,449.60	2,145.20
Amortizable intangible assets - net	1,776	1,078.80
Total assets	10,010	6,860.50
Premiums payable to insurance and reinsurance companies	2,623.30	2,154.70
Accrued compensation and other accrued liabilities	623.7	370.6
Unearned fees	66.1	84.5
Other current liabilities	61.7	44.5
Premium financing borrowings	127.9
Corporate related borrowings - current	140	630.5
Total current liabilities	3,642.70	3,284.80
Corporate related borrowings - noncurrent	2,125	825
Other noncurrent liabilities	1,012.90	665.2
Total liabilities	6,780.60	4,775
Stockholders' equity:
Common stock - authorized 400.0 shares; issued and outstanding 164.6 shares in 2014 and 133.6 shares in 2013	164.6	133.6
Capital in excess of par value	2,649.40	1,358.10
Retained earnings	676	596.4
Accumulated other comprehensive loss	-260.6	-2.6
Total stockholders' equity	3,229.40	2,085.50
Total liabilities and stockholders' equity	$10,010	$6,860.50

Consolidated_Balance_Sheet_Par

Consolidated Balance Sheet (Parenthetical)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common stock - authorized shares	400,000,000	400,000,000
Common stock - issued shares	164,600,000	133,600,000
Common stock - outstanding shares	164,600,000	133,600,000

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net earnings	$303.40	$268.60	$195
Adjustments to reconcile net earnings to net cash provided by operating activities:
Net gain on investments and other	-23	-17.1	-3.9
Depreciation and amortization	258.9	178.6	140.4
Change in estimated acquisition earnout payables	17.5	1.7	3.4
Amortization of deferred compensation and restricted stock	22.9	19	8.3
Stock-based and other noncash compensation expense	10.6	7.7	7.5
Effect of changes in foreign exchange rate	-0.5	-0.2	1.9
Net change in restricted cash	-62.1	-58.6	-90.2
Net change in premiums receivable	95.3	-85.4	11.5
Net change in premiums payable	60	114.3	33.3
Net change in other current assets	-150.5	-57.4	52.4
Net change in accrued compensation and other accrued liabilities	184.2	36.3	19.2
Net change in fees receivable/unearned fees	-26	-5.9	4.3
Net change in income taxes payable	4.9	4.3	14
Net change in deferred income taxes	-126.1	-53.8	-20.4
Net change in other noncurrent assets and liabilities	-167.2	-2.2	-33.7
Net cash provided by operating activities	402.3	349.9	343
Cash flows from investing activities:
Net additions to fixed assets	-81.5	-93.6	-51
Cash paid for acquisitions, net of cash acquired	-1,918.30	-727.7	-344.1
Net proceeds from sales of operations/books of business	8.2	5.5	11.4
Net (funding) proceeds of investment transactions	-20.1	-35.9	1.5
Net cash used by investing activities	-2,011.70	-851.7	-382.2
Cash flows from financing activities:
Proceeds from issuance of common stock	997	76.2	82.3
Tax impact from issuance of common stock	6.9	7.5	0.5
Repurchases of common stock			-1.5
Dividends paid	-223.1	-182.6	-204.4
Net borrowings on premium financing debt facility	7.5
Borrowings on line of credit facilities	1,109.90	890.5	303
Repayments on line of credit facilities	-1,500.40	-489	-184
Net borrowings of corporate related long-term debt	1,200	200	50
Net cash provided by financing activities	1,597.80	502.6	45.9
Effect of changes in foreign exchange rates on cash and cash equivalents	27.9	-4.8	4.2
Net increase (decrease) in cash and cash equivalents	16.3	-4	10.9
Cash and cash equivalents at beginning of year	298.1	302.1	291.2
Cash and cash equivalents at end of year	314.4	298.1	302.1
Supplemental disclosures of cash flow information:
Interest paid	82.5	49.2	42.2
Income taxes paid	$72.90	$49.20	$47.50

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Earnings (Loss) [Member]
In Millions, unless otherwise specified	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Earnings (Loss) [Member]
Beginning Balance at Dec. 31, 2011	$1,243.60	$114.70	$693.20	$482.90	($47.20)
Beginning Balance (in shares) at Dec. 31, 2011		114.7
Net earnings	195			195
Net change in pension asset/liability, net of taxes	-3.4				-3.4
Foreign currency translation	16.1				16.1
Change in fair value of derivative instruments, net of taxes	1.7				1.7
Compensation expense related to stock option plan grants	7.2		7.2
Tax impact from issuance of common stock	0.5		0.5
Common stock issued in:
Purchase transactions	276.3	7.8	268.5
Purchase transactions (in shares)		7.8
Stock option plans	73.9	2.8	71.1
Stock option plans (in shares)	2.8	2.8
Employee stock purchase plan	8.4	0.3	8.1
Employee stock purchase plan (in shares)		0.3
Deferred compensation/restricted stock	8	0.1	7.9
Deferred compensation/restricted stock (in shares)		0.1
Other compensation expense	0.3		0.3
Common stock repurchases	-1.5	-0.1	-1.4
Common stock repurchases (in shares)		-0.1
Cash dividends declared on common stock	-167.5			-167.5
Ending Balance at Dec. 31, 2012	1,658.60	125.6	1,055.40	510.4	-32.8
Ending Balance (in shares) at Dec. 31, 2012		125.6
Net earnings	268.6			268.6
Net change in pension asset/liability, net of taxes	26.8				26.8
Foreign currency translation	1.6				1.6
Change in fair value of derivative instruments, net of taxes	1.8				1.8
Compensation expense related to stock option plan grants	7.7		7.7
Tax impact from issuance of common stock	7.5		7.5
Common stock issued in:
Purchase transactions	232.2	5.2	227
Purchase transactions (in shares)		5.2
Stock option plans	61.8	2.3	59.5
Stock option plans (in shares)	2.3	2.3
Employee stock purchase plan	10.2	0.3	9.9
Employee stock purchase plan (in shares)		0.3
Deferred compensation/restricted stock	-13	0.1	-13.1
Deferred compensation/restricted stock (in shares)		0.1
Stock issuance under dribble-out program	4.3	0.1	4.2
Stock issuance under dribble-out program (in shares)		0.1
Cash dividends declared on common stock	-182.6			-182.6
Ending Balance at Dec. 31, 2013	2,085.50	133.6	1,358.10	596.4	-2.6
Ending Balance (in shares) at Dec. 31, 2013		133.6
Net earnings	303.4			303.4
Net change in pension asset/liability, net of taxes	-18.6				-18.6
Foreign currency translation	-238.4				-238.4
Change in fair value of derivative instruments, net of taxes	-1				-1
Compensation expense related to stock option plan grants	9.5		9.5
Tax impact from issuance of common stock	6.9		6.9
Common stock issued in:
Purchase transactions	299.3	6.5	292.8
Purchase transactions (in shares)		6.5
Stock option plans	44.2	1.6	42.6
Stock option plans (in shares)	1.7	1.6
Employee stock purchase plan	12.4	0.3	12.1
Employee stock purchase plan (in shares)		0.3
Deferred compensation/restricted stock	8.5	0.1	8.4
Deferred compensation/restricted stock (in shares)		0.1
Stock issuance under dribble-out program	29	0.6	28.4
Stock issuance under dribble-out program (in shares)		0.6
Stock issuance from public offering	911.4	21.9	889.5
Stock issuance from public offering (in shares)		21.9
Other compensation expense	1.1		1.1
Cash dividends declared on common stock	-223.8			-223.8
Ending Balance at Dec. 31, 2014	$3,229.40	$164.60	$2,649.40	$676	($260.60)
Ending Balance (in shares) at Dec. 31, 2014		164.6

Consolidated_Statement_of_Stoc1

Consolidated Statement of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Tax effect on net change in pension liability	$12.40	$17.90	($0.20)
Net change in fair value of derivative instruments, tax	($0.70)	$1.30	$1.10

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies
	Nature of Operations - 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 30 countries and offer client-service capabilities in more than 140 countries globally through a network of correspondent insurance brokers and consultants.
	Basis of Presentation - 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.
	Certain reclassifications have been made to the amounts reported in prior years’ consolidated financial statements in order to conform to the current year presentation.
	In the preparation of our consolidated financial statements as of December 31, 2014, 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.
	Use of Estimates - 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.
	Revenue Recognition - Our revenues are derived from commissions, fees and investment income.
	We recognize commission revenues at the later of the billing or the effective date of the related insurance policies, net of an allowance for estimated policy cancellations. We recognize commission revenues related to installment premiums as the installments are billed. We recognize supplemental commission revenues using internal data and information received from insurance carriers that allows us to reasonably estimate the supplemental commissions earned in the period. A supplemental commission is a commission paid by an insurance carrier that is above the base commission paid, is determined by the insurance carrier, and is established annually in advance of the contractual period based on historical performance criteria. We recognize contingent commissions and commissions on premiums directly billed by insurance carriers as revenue when we have obtained the data necessary to reasonably determine such amounts. Typically, we cannot reasonably determine these types of commission revenues until we have received the cash or the related policy detail or other carrier specific information from the insurance carrier. A contingent commission is a commission paid by an insurance carrier based on the overall profit and/or volume of the business placed with that insurance carrier during a particular calendar year and is determined after the contractual period. Commissions on premiums billed directly by insurance carriers to the insureds generally relate to a large number of property/casualty insurance policy transactions, each with small premiums, and comprise a substantial portion of the revenues generated by our employee benefit brokerage operations. Under these direct bill arrangements, the insurance carrier controls the entire billing and policy issuance process. We record the income effects of subsequent premium adjustments when the adjustments become known.
	Fee revenues generated from the brokerage segment primarily relate to fees negotiated in lieu of commissions that we recognize in the same manner as commission revenues. Fee revenues generated from the risk management segment relate to third party claims administration, loss control and other risk management consulting services, which we provide over a period of time, typically one year. We recognize these fee revenues ratably as the services are rendered, and record the income effects of subsequent fee adjustments when the adjustments become known.

	We deduct brokerage expense from gross revenues in our determination of our total revenues. Brokerage expense represents commissions paid to sub-brokers related to the placement of certain business by our brokerage segment. We recognize this expense in the same manner as commission revenues.
	Premiums and fees receivable in the accompanying consolidated balance sheet are net of allowances for estimated policy cancellations and doubtful accounts. The allowance for estimated policy cancellations was $6.8 million and $4.2 million at December 31, 2014 and 2013, respectively, which represents a reserve for future reversals in commission and fee revenues related to the potential cancellation of client insurance policies that were in force as of each year end. The allowance for doubtful accounts was $10.7 million and $6.7 million at December 31, 2014 and 2013, respectively. We establish the allowance for estimated policy cancellations through a charge to revenues and the allowance for doubtful accounts through a charge to operating expenses. Both of these allowances are based on estimates and assumptions using historical data to project future experience. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein. We periodically review the adequacy of these allowances and make adjustments as necessary.
	Investment income primarily includes interest and dividend income (including interest income from our premium financing operations), which is accrued as it is earned. Gains on books of business sales represent one-time gains related to sales of brokerage related businesses, which are primarily recognized on a cash received basis. Revenues from clean coal activities include revenues from consolidated clean coal production plants, royalty income from clean coal licenses and income (loss) related to unconsolidated clean coal production plants, all of which are recognized as earned. Revenues from consolidated clean coal production plants represent sales of refined coal. Royalty income from clean coal licenses represents fee income related to the use of clean coal technologies. Income (loss) from unconsolidated clean coal production plants includes income (losses) related to our equity portion of the pretax results of the clean coal production plants and production based installment sale income from majority investors.
	Claims Handling Obligations - We are obligated under certain circumstances to provide future claims handling and certain administrative services for our former global risks brokerage clients in the U.K. Our obligation is the result of following the industry practice of insurance brokers providing future claims handling and administrative services to former clients. In addition, under certain circumstances, our risk management segment operations are contractually obligated to provide contract claim settlement and administration services to our former clients. Accordingly, we record a liability for these deferred run-off obligations based on the estimated costs to provide these future services to former clients. This liability is based on estimates and assumptions using historical data to project future experience. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein. We periodically review (at least annually) the adequacy of this liability and will make adjustments as necessary.
	Earnings per Share - Basic net earnings per share is computed by dividing net earnings by the weighted average number of common shares outstanding during the reporting period. Diluted net earnings per share is computed by dividing net earnings by the weighted average number of common and common equivalent shares outstanding during the reporting period. Common equivalent shares include incremental shares from dilutive stock options, which are calculated from the date of grant under the treasury stock method using the average market price for the period.
	Cash and Cash Equivalents - Short-term investments, consisting principally of cash and money market accounts that have average maturities of 90 days or less, are considered cash equivalents.
	Restricted Cash - In our capacity as an insurance broker, we collect premiums from insureds and, after deducting our commissions and/or fees, remit these premiums to insurance carriers. We hold unremitted insurance premiums in a fiduciary capacity until we disburse them, and the use of such funds is restricted by laws in certain states and foreign jurisdictions in which our subsidiaries operate. Various state and foreign agencies regulate insurance brokers and provide specific requirements that limit the type of investments that may be made with such funds. Accordingly, we invest these funds in cash and U.S. Treasury fund accounts. We can earn interest income on these unremitted funds, which is included in investment income in the accompanying consolidated statement of earnings. These unremitted amounts are reported as restricted cash in the accompanying consolidated balance sheet, with the related liability reported as premiums payable to insurance and reinsurance companies. Additionally, several of our foreign subsidiaries are required by various foreign agencies to meet certain liquidity and solvency requirements. We were in compliance with these requirements at December 31, 2014.
	Related to our third party administration business, we are responsible for client claim funds that we hold in a fiduciary capacity. We do not earn any interest income on the funds held. These client funds have been included in restricted cash, along with a corresponding liability in premiums payable to insurance and reinsurance companies in the accompanying consolidated balance sheet.
	Derivative Instruments - In the normal course of business, we are exposed to the impact of foreign currency fluctuations that impact our results of operations and cash flows. We utilize a foreign currency risk management program involving foreign currency derivatives that consist of several monthly put/call options designed to hedge a significant portion of our future foreign currency disbursements through various future payment dates. To mitigate the counterparty credit risk we only enter into contracts with carefully selected major financial institutions based upon their credit ratings and other factors. These derivative instrument contracts are cash flow hedges that qualify for hedge accounting and primarily hedge against fluctuations between changes in the British Pound Sterling and Indian Rupee versus the U.S. Dollar. Changes in fair value of the derivative instruments are reflected in other comprehensive earnings in the accompanying consolidated balance sheet. The impact of the hedge at maturity is recognized in the income statement as a component of compensation and operating expenses. These derivative instrument contracts are periodically monitored for hedge ineffectiveness, the amount of which has not been material to the accompanying consolidated financial statements. We do not use derivatives for trading or speculative purposes. In 2014, other net revenues also includes a gain of $1.9 million related to a AU$400.0 million foreign currency derivative investment contract that we executed on April 16, 2014 in connection with the signing of the agreement to acquire the Crombie/OAMPS operations, headquartered in Australia. This contract was designed to hedge a portion of the AU$ denominated purchase price consideration of this acquisition. The derivative investment contract was exercised on June 16, 2014, the date that the Crombie/OAMPS transaction closed. In 2013, other net revenues also includes a gain of $2.6 million related to three foreign currency derivative investment contracts that we executed in September 2013 in connection with the signing of an agreement to acquire The Giles Group of Companies, headquartered in London, England. These contracts were designed to hedge a portion of the GBP denominated purchase price consideration of this acquisition. The derivative investment contracts were exercised on October 31, 2013 and the Giles transaction closed in early November 2013.
	Premium Financing - Seven subsidiaries of the brokerage segment make short-term loans (generally with terms of twelve months or less) to our clients to finance premiums. These 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. We recognize interest income as it is earned over the life of the contract using the “level-yield” method. Unearned interest related to contracts receivable is included in the receivable balance in the accompanying consolidated balance sheet. The outstanding loan receivable balance was $232.6 million and $2.3 million at December 31, 2014 and 2013, respectively.
	Fixed Assets - We carry fixed assets at cost, less accumulated depreciation, in the accompanying consolidated balance sheet. We periodically review long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying value of the assets may not be recoverable. Under those circumstances, if the fair value were less than the carrying amount of the asset, we would recognize a loss for the difference. Depreciation for fixed assets is computed using the straight-line method over the following estimated useful lives:


			Useful Life
	Computer equipment		Three to five years
	Furniture and fixtures		Three to ten years
	Office equipment		Three to ten years
	Software		Three to five years
	Refined fuel plants		Ten years
	Leasehold improvements		Shorter of the lease term or useful life of the asset
	Intangible Assets - Intangible assets represent the excess of cost over the estimated fair value of net tangible assets of acquired businesses. Our primary intangible assets are classified as either goodwill, expiration lists, non-compete agreements or trade names. Expiration lists, non-compete agreements and trade names are amortized using the straight-line method over their estimated useful lives (three to fifteen years for expiration lists, three to five years for non-compete agreements and five to fifteen years for trade names), while goodwill is not subject to amortization. The establishment of goodwill, expiration lists, non-compete agreements and trade names and the determination of estimated useful lives are primarily based on valuations we receive from qualified independent appraisers. The calculations of these amounts are based on estimates and assumptions using historical and projected financial information and recognized valuation methods. Different estimates or assumptions could produce different results. We carry intangible assets at cost, less accumulated amortization, in the accompanying consolidated balance sheet.
	We review all of our intangible assets for impairment periodically (at least annually for goodwill) and whenever events or changes in business circumstances indicate that the carrying value of the assets may not be recoverable. We perform such impairment reviews at the division (i.e., reporting unit) level with respect to goodwill and at the business unit level for amortizable intangible assets. In reviewing intangible assets, if the fair value were less than the carrying amount of the respective (or underlying) asset, an indicator of impairment would exist and further analysis would be required to determine whether or not a loss would need to be charged against current period earnings as a component of amortization expense. Based on the results of impairment reviews in 2014, 2013 and 2012, we wrote off $1.8 million, $2.2 million and $3.5 million, respectively, of amortizable intangible assets primarily related to prior year acquisitions of our brokerage segment, which is included in amortization expense in the accompanying consolidated statement of earnings. The determinations of impairment indicators and fair value are based on estimates and assumptions related to the amount and timing of future cash flows and future interest rates. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein.

	Income Taxes - Our tax rate reflects the statutory tax rates applicable to our taxable earnings and tax planning in the various jurisdictions in which we operate. Significant judgment is required in determining the annual effective tax rate and in evaluating uncertain tax positions. We report a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in our tax return. We evaluate our tax positions using a two-step process. The first step involves recognition. We determine whether it is more likely than not that a tax position will be sustained upon tax examination based solely on the technical merits of the position. The technical merits of a tax position are derived from both statutory and judicial authority (legislation and statutes, legislative intent, regulations, rulings and case law) and their applicability to the facts and circumstances of the position. If a tax position does not meet the “more likely than not” recognition threshold, we do not recognize the benefit of that position in the financial statements. The second step is measurement. A tax position that meets the “more likely than not” recognition threshold is measured to determine the amount of benefit to recognize in the financial statements. The tax position is measured as the largest amount of benefit that has a likelihood of greater than 50% of being realized upon ultimate resolution with a taxing authority.
	Uncertain tax positions are measured based upon the facts and circumstances that exist at each reporting period and involve significant management judgment. Subsequent changes in judgment based upon new information may lead to changes in recognition, derecognition and measurement. Adjustments may result, for example, upon resolution of an issue with the taxing authorities, or expiration of a statute of limitations barring an assessment for an issue. We recognize interest and penalties, if any, related to unrecognized tax benefits in our provision for income taxes.
	Tax law requires certain items to be included in our tax returns at different times than such items are reflected in the financial statements. As a result, the annual tax expense reflected in our consolidated statements of earnings is different than that reported in our tax returns. Some of these differences are permanent, such as expenses that are not deductible in our tax returns, and some differences are temporary and reverse over time, such as depreciation expense and amortization expense deductible for income tax purposes. Temporary differences create deferred tax assets and liabilities. Deferred tax liabilities generally represent tax expense recognized in the financial statements for which a tax payment has been deferred, or expense which has been deducted in the tax return but has not yet been recognized in the financial statements. Deferred tax assets generally represent items that can be used as a tax deduction or credit in tax returns in future years for which a benefit has already been recorded in the financial statements.
	We establish or adjust valuation allowances for deferred tax assets when we estimate that it is more likely than not that future taxable income will be insufficient to fully use a deduction or credit in a specific jurisdiction. In assessing the need for the recognition of a valuation allowance for deferred tax assets, we consider whether it is more likely than not that some portion, or all, of the deferred tax assets will not be realized and adjust the valuation allowance accordingly. We evaluate all significant available positive and negative evidence as part of our analysis. Negative evidence includes the existence of losses in recent years. Positive evidence includes the forecast of future taxable income by jurisdiction, tax-planning strategies that would result in the realization of deferred tax assets and the presence of taxable income in prior carryback years. The underlying assumptions we use in forecasting future taxable income require significant judgment and take into account our recent performance. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the periods in which temporary differences are deductible or creditable.
	Fair Value of Financial Instruments - Fair value accounting establishes a framework for measuring fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (i.e., an exit price). This framework includes a fair value hierarchy that prioritizes the inputs to the valuation technique used to measure fair value.
	The classification of a financial instrument within the valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels of the hierarchy in order of priority of inputs to the valuation technique are defined as follows:

		•		Level 1 - Valuations are based on unadjusted quoted prices in active markets for identical financial instruments;

		•		Level 2 - Valuations are based on quoted market prices, other than quoted prices included in Level 1, in markets that are not active or on inputs that are observable either directly or indirectly for the full term of the financial instrument; and

		•		Level 3 - Valuations are based on pricing or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement of the financial instrument. Such inputs may reflect management’s own assumptions about the assumptions a market participant would use in pricing the financial instrument.
	The level in the fair value hierarchy within which the fair value measurement is classified is determined based on the lowest level input that is significant to the fair value measure in its entirety.
	The carrying amounts of financial assets and liabilities reported in the accompanying consolidated balance sheet for cash and cash equivalents, restricted cash, premiums and fees receivable, premiums payable to insurance carriers, accrued salaries and bonuses, accounts payable and other accrued liabilities, unearned fees and income taxes payable, at December 31, 2014 and 2013, approximate fair value because of the short-term duration of these instruments. See Note 3 to our consolidated financial statements for the fair values related to the establishment of intangible assets and the establishment and adjustment of earnout payables. See Note 7 to our consolidated financial statements for the fair values related to borrowings outstanding at December 31, 2014 and 2013 under our debt agreements. See Note 12 to our consolidated financial statements for the fair values related to investments at December 31, 2014 and 2013 under our defined benefit pension plan.
	Litigation - We are the defendant in various legal actions related to claims, lawsuits and proceedings incident to the nature of our business. We record liabilities for loss contingencies, including legal costs (such as fees and expenses of external lawyers and other service providers) to be incurred, when it is probable that a liability has been incurred on or before the balance sheet date and the amount of the liability can be reasonably estimated. We do not discount such contingent liabilities. To the extent recovery of such losses and legal costs is probable under our insurance programs, we record estimated recoveries concurrently with the losses recognized. Significant management judgment is required to estimate the amounts of such contingent liabilities and the related insurance recoveries. In order to assess our potential liability, we analyze our litigation exposure based on available information, including consultation with outside counsel handling the defense of these matters. As these liabilities are uncertain by their nature, the recorded amounts may change due to a variety of different factors, including new developments in, or changes in approach, such as changing the settlement strategy as applicable to each matter.
	Stock-Based Compensation - We have several employee equity-settled and cash-settled share-based compensation plans. Equity-settled share-based payments to employees include grants of stock options and restricted stock units and are measured based on estimated grant date fair value. We have elected to use the Black-Scholes option pricing model to determine the fair value of stock options on the dates of grant. Restricted stock units are measured based on the fair market values of the underlying stock on the dates of grant. Shares are issued on the vesting dates net of the minimum statutory tax withholding requirements, as applicable, to be paid by us on behalf of our employees. As a result, the actual number of shares issued will be fewer than the actual number of restricted stock units outstanding. Furthermore, we record the liability for withholding amounts to be paid by us as a reduction to additional paid-in capital when paid.
	Cash-settled share-based payments to employees include grants of performance units and stock appreciation rights. The fair value of the amount payable to employees in respect of cash-settled share-based payments is recognized as compensation expense, with a corresponding increase in liabilities, over the vesting period. The liability is remeasured at each reporting date and at settlement date. Any changes in fair value of the liability are recognized as compensation expense.
	We recognize share-based compensation expense over the requisite service period for awards expected to ultimately vest. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs from original estimates.
	Employee Stock Purchase Plan - We have an employee stock purchase plan (which we refer to as the ESPP), under which the sale of 4.0 million shares of our common stock has been authorized. Eligible employees may contribute up to 15% of their compensation towards the quarterly purchase of our common stock at a purchase price equal to 95% of the lesser of the fair market value of our common stock on the first business day or the last business day of the quarterly offering period. Eligible employees may annually purchase shares of our common stock with an aggregate fair market value of up to $25,000 (measured as of the first day of each quarterly offering period of each calendar year), provided that no employee may purchase more than 2,000 shares of our common stock under the ESPP during any calendar year. At December 31, 2014, 0.3 million shares of our common stock are reserved for future issuance under the ESPP.
	Defined Benefit Pension and Other Postretirement Plans - We recognize in our consolidated balance sheet, an asset for our defined benefit postretirement plans’ overfunded status or a liability for our plans’ underfunded status. We recognize changes in the funded status of our defined benefit postretirement plans in comprehensive earnings in the year in which the changes occur. We use December 31 as the measurement date for our plans’ assets and benefit obligations. See Note 12 to our consolidated financial statements for additional information required to be disclosed related to our defined benefit postretirement plans.

Effect_of_New_Accounting_Prono

Effect of New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Effect of New Accounting Pronouncements	2	Effect of New Accounting Pronouncements
	Revenue Recognition
	In May 2014, the Financial Accounting Standards Board (which we refer to as the FASB) issued new accounting guidance on revenue from contracts with customers, which will supersede nearly all existing revenue recognition guidance under U.S. GAAP. The core principal of the new guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. This new guidance is effective for the first quarter of 2017 and early adoption is not permitted. The guidance permits two methods of transition upon adoption; full retrospective and modified retrospective. Under the full retrospective method, prior periods would be restated under the new revenue standard, providing a comparable view across all periods presented. Under the modified retrospective method, prior periods would not be restated. Rather, revenues and other disclosures for pre-2017 periods would be provided in the notes to the financial statements as previously reported under the current revenue standard. Management is currently reviewing the guidance, and the impact from its adoption on our consolidated financial statements cannot be determined at this time.
	Presentation of Unrecognized Tax Benefits
	In July 2013, the FASB issued ASU 2013 11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists,” which provides explicit guidance on the presentation of certain unrecognized tax benefits in the financial statements that did not previously exist. The guidance provides that a liability related to an unrecognized tax benefit would be offset against a deferred tax asset for a net operating loss carryforward, a similar tax loss or a tax credit carryforward if such settlement is required or expected in the event the uncertain tax position is disallowed. In that case, the liability associated with the unrecognized tax benefit is presented in the financial statements as a reduction to the related deferred tax asset. In situations in which a net operating loss carryforward, a similar tax loss or a tax credit carryforward is not available at the reporting date under the tax law of the jurisdiction or the tax law of the jurisdiction does not require, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit will be presented in the financial statements as a liability and will not be combined with deferred tax assets. This new guidance was effective in first quarter 2014. We adopted the new guidance effective January 1, 2014. The impact of the new guidance upon adoption was not material to our 2014 consolidated financial statements.

Business_Combinations

Business Combinations	12 Months Ended
Business Combinations	Dec. 31, 2014
Business Combinations [Abstract]
Business Combinations	3	Business Combinations
	During 2014, we acquired substantially all of the net assets of the following firms in exchange for our common stock and/or cash. These acquisitions have been accounted for using the acquisition method for recording business combinations (in millions except share data):


	Name and Effective Date		Common				Common			Cash			Accrued			Escrow			Recorded			Total			Maximum
	of Acquisition		Shares				Share			Paid			Liability			Deposited			Earnout			Recorded			Potential
			Issued				Value												Payable			Purchase			Earnout
																						Price			Payable
				(000s	)
	Benefit Development			46			$	2		$	0.7		$	—		$	0.1		$	0.6		$	3.4		$	2
	Group, Inc.
	February 1, 2014
	Kent, Kent & Tingle			229				9.1			3.5			—			1.4			3.5			17.5			7.8
	February 1, 2014			229				9.1			3.5			—			1.4			3.5			17.5			7.8
	L&R Benefits, LLC			115				5.3			1.8			—			0.1			1			8.2			6
	March 1, 2014			115				5.3			1.8			—			0.1			1			8.2			6
	Spataro Insurance Agency, Inc. March 1, 2014			47				2			—			—			0.2			0.4			2.6			0.6
	Tudor Risk Services, LLC			—				—			2.1			—			0.2			0.1			2.4			1.3
	March 1, 2014			—				—			2.1			—			0.2			0.1			2.4			1.3
	American Wholesalers Underwriting Ltd April 1, 2014			133				6			5.7			—			0.5			—			12.2			—
	Mike Henry Insurance Brokers Limited April 1, 2014			—				—			9.6			—			1.7			4.2			15.5			5
	Oval Group of Companies (OGC) April 1, 2014			—				—			338.4			—			11.8			—			350.2			—
	Heritage Insurance Management Limited (HIM) May 1, 2014			—				—			33.9			—			3.8			—			37.7			—
	MGA Insurance Group (MGA) May 1, 2014			547				25.1			26.8			—			2.5			11.9			66.3			20
	Shilling Limited May 1, 2014			198				8.9			1.7			—			1.2			1			12.8			8.4
	Sunderland Insurance Services, Inc. May 1, 2014			204				9.2			2.4			—			0.6			—			12.2			—
	Plus Companies, Inc. June 1, 2014			221				9.3			3.4			—			0.8			—			13.5			—
	Tri-State General Insurance Agency, Inc. June 1, 2014			47				2.2			0.6			—			0.1			—			2.9			—
	Crombie/OAMPS (CO) June 16, 2014			—				—			993.1			—			—			—			993.1			—
	Foundation Strategies, Inc. July 1, 2014			46				2			0.7			—			0.1			0.4			3.2			3
	Insurance Point, LLC July 1, 2014			255				11.2			3.9			—			0.5			2.6			18.2			24.4
				(000s	)
	Trip Mate, Inc. July 1, 2014			209			$	8.4		$	3.9		$	—		$	1		$	3.7		$	17		$	12.5
	Noraxis Capital Corporation (NCC) July 2, 2014			—				—			413.3			—			1.9			—			415.2			—
	Cowles & Connell August 1, 2014			331				14.8			4.2			—			0.8			—			19.8			—
	Denman Consulting Services August 1, 2014			40				1.7			0.6			—			0.1			0.3			2.7			1.6
	Minvielle & Chastanet Insurance Brokers August 8, 2014			—				—			5			—			—			3			8			5
	Baker Tilly Financial Management Limited August 29, 2014			185				8.7			2.3			—			0.7			4.7			16.4			5.4
	Benfield Group September 1, 2014			82				3.8			1.1			—			0.1			0.9			5.9			3.5
	Everett James, Inc. September 1, 2014			52				2.4			0.7			—			0.1			0.8			4			4
	Hagedorn & Company September 1, 2014			281				11.5			—			—			1.3			—			12.8			—
	Parmia Pty Ltd. September 1, 2014			—				—			1.7			—			—			1.2			2.9			1.2
	Bennett and Shade Company October 1, 2014			35				1.5			0.5			—			0.2			—			2.2			—
	Insurance Associates, Inc. October 1, 2014			169				7.2			—			—			0.8			1.1			9.1			3
	Forker Company October 31, 2014			24				1.1			0.3			—			0.1			1.6			3.1			2.2
	Discovery Benefit Solutions, Inc. November 1, 2014			115				5.4			—			—			0.1			1.4			6.9			4.5
	Miller-Harrison Insurance Services November 1, 2014			38				1.8			—			—			—			0.6			2.4			1
	SGB-NIA Insurance Brokers (SGB) November 1, 2014			449				18.7			7.2			—			2.9			4.2			33			5.2
	Titan Group LLC November 1, 2014			49				2.4			—			—			0.1			0.4			2.9			2
	Instrat Insurance Brokers December 1, 2014			—				—			16.2			—			—			9.5			25.7			9.5
	O’Gorman & Young Incorporated (OGY) December 1, 2014			554				23.8			—			—			2.7			6.4			32.9			12.5
				(000s	)
	Independent Benefit Services, Inc. (IBS) December 1, 2014			395			$	17.8		$	6.2		$	—		$	0.8		$	1.3		$	26.1		$	14.3
	Affinity Marketing Group December 1, 2014			72				3.1			—			—			0.3			2.2			5.6			5.2
	Blue Holdings Group of Companies December 5, 2014			227				10.9			4.5			—			1.7			1.2			18.3			6.6
	Twenty-one other acquisitions completed in 2014			344				14.8			18.5			—			1.1			10.3			44.7			21.1

				5,739			$	252.1		$	1,914.50		$	—		$	42.4		$	80.5		$	2,289.50		$	198.8

	On April 1, 2014, we closed on an agreement to acquire the Oval Group of Companies (which we refer to as Oval). Under the agreement, we agreed to purchase all of the outstanding equity of Oval for net cash consideration of approximately $338.0 million. Oval was an independent commercial insurance broker operating out of 24 offices throughout the U.K., with over 1,000 employees.
	On April 16, 2014, we closed on a secondary public offering of our common stock whereby 21.85 million shares of our stock were issued for net proceeds, after underwriting discounts and other expenses related to this offering, of $911.4 million. We used the net proceeds of the offering to fund acquisitions.
	On June 16, 2014, we closed on an agreement to acquire the Wesfarmers Insurance Brokerage operations (which we refer to as Crombie/OAMPS). The Crombie/OAMPS transaction, includes the OAMPS businesses in Australia and the U.K., Crombie in New Zealand and the associated premium funding operations. Under the agreement, we agreed to purchase all of the outstanding shares of these three operating companies for net cash consideration of approximately $952.0 million, plus an additional $35.3 million on October 14, 2014 related to a true-up of the excess of net current assets based on the final acquisition date balance sheet over the target amount as set forth in the acquisition agreement. The Crombie/OAMPS operations have approximately 1,700 employees operating out of more than 50 offices across Australia, New Zealand and the U.K.
	On July 2, 2014, we closed on an agreement to acquire Noraxis Capital Corporation (which we refer to as Noraxis), paying cash consideration of approximately $415.0 million for approximately 89% of the equity of Noraxis. The remaining equity is held by various management employees of Noraxis. Noraxis has more than 650 employees in offices across Alberta, Manitoba, New Brunswick, Nova Scotia and Ontario.
	Common shares issued in connection with acquisitions are valued at closing market prices as of the effective date of the applicable acquisition. We record escrow deposits that are returned to us as a result of adjustments to net assets acquired as reductions of goodwill when the escrows are settled. The maximum potential earnout payables disclosed in the foregoing table represent the maximum amount of additional consideration that could be paid pursuant to the terms of the purchase agreement for the applicable acquisition. The amounts recorded as earnout payables, which are primarily based upon the estimated future operating results of the acquired entities over a two- to three-year period subsequent to the acquisition date, are measured at fair value as of the acquisition date and are included on that basis in the recorded purchase price consideration in the foregoing table. We will record subsequent changes in these estimated earnout obligations, including the accretion of discount, in our consolidated statement of earnings when incurred.
The fair value of these earnout obligations is based on the present value of the expected future payments to be made to the sellers of the acquired entities in accordance with the provisions outlined in the respective purchase agreements, which is a Level 3 fair value measurement. In determining fair value, we estimated the acquired entity’s future performance using financial projections developed by management for the acquired entity and market participant assumptions that were derived for revenue growth and/or profitability. Revenue growth rates generally ranged from 4.0% to 12.0% for our 2014 acquisitions. We estimated future payments using the earnout formula and performance targets specified in each purchase agreement and these financial projections. We then discounted these payments to present value using a risk-adjusted rate that takes into consideration market-based rates of return that reflect the ability of the acquired entity to achieve the targets. These discount rates generally ranged from 8.5% to 9.5% for our 2014 acquisitions. Changes in financial projections, market participant assumptions for revenue growth and/or profitability, or the risk-adjusted discount rate, would result in a change in the fair value of recorded earnout obligations.

During 2014, 2013 and 2012, we recognized $14.5 million, $11.9 million and $9.3 million, respectively, of expense in our consolidated statement of earnings related to the accretion of the discount recorded for earnout obligations in connection with our acquisitions. In addition, during 2014, 2013 and 2012 we recognized $3.0 million of expense, $10.2 million and $5.9 million of income, respectively, related to net adjustments in the estimated fair value of the liability for earnout obligations in connection with revised projections of future performance for 67, 79 and 46 acquisitions, respectively. The aggregate amount of maximum earnout obligations related to acquisitions made in 2011 and subsequent years was $549.8 million as of December 31, 2014, of which $205.3 million was recorded in the consolidated balance sheet as of that date based on the estimated fair value of the expected future payments to be made. The aggregate amount of maximum earnout obligations related to acquisitions made in 2010 and subsequent years was $462.3 million as of December 31, 2013, of which $162.7 million was recorded in the consolidated balance sheet as of that date based on the estimated fair value of the expected future payments to be made.
The following is a summary of the estimated fair values of the net assets acquired at the date of each acquisition made in 2014 (in millions):


		OGC				HIM			MGA			CO			NCC			SGB			OGY			IBS			Fifty-Two		Total
																											Other
																											Acquisitions
Cash		$	23.1			$	2.9		$	0.2		$	26.6		$	10.1		$	—		$	—		$	—		$	5.8	$	68.7
Other current assets			129.6				4.9			8.9			695.5			73			0.7			2.8			0.5			59.2		975.1
Fixed assets			2.1				0.3			0.8			17.1			4.9			0.1			0.2			—			4.3		29.8
Noncurrent assets			—				—			—			7			3.5			0.1			—			—			4.9		15.5
Goodwill			245.7				14.8			27			619.6			314.9			14.9			25.8			12.7			172.9		1,448.30
Expiration lists			129.9				20.3			33.2			325.3			178.6			17.8			18.7			13.1			159		895.9
Non-compete agreements			1				1.3			0.3			4.2			2.6			0.1			0.3			0.2			1.9		11.9
Trade names			0.6				—			—			4.2			2.2			—			—			—			2.4		9.4

Total assets acquired			532				44.5			70.4			1,699.50			589.8			33.7			47.8			26.5			410.4		3,454.60

Current liabilities			129.5				6.8			4.1			490			72.5			0.7			4.1			0.4			63		771.1
Noncurrent liabilities			52.3				—			—			216.4			102.1			—			10.8			—			12.4		394

Total liabilities assumed			181.8				6.8			4.1			706.4			174.6			0.7			14.9			0.4			75.4		1,165.10

Total net assets acquired		$	350.2			$	37.7		$	66.3		$	993.1		$	415.2		$	33		$	32.9		$	26.1		$	335	$	2,289.50

Among other things, these acquisitions allow us to expand into desirable geographic locations, further extend our presence in the retail and wholesale insurance brokerage services and risk management industries and increase the volume of general services currently provided. The excess of the purchase price over the estimated fair value of the tangible net assets acquired at the acquisition date was allocated to goodwill, expiration lists, non-compete agreements and trade names in the amounts of $1,448.3 million, $895.9 million, $11.9 million and $9.4 million, respectively, within the brokerage segment.
Provisional estimates of fair value are established at the time of the acquisition and are subsequently reviewed within the first year of operations subsequent to the acquisition date to determine the necessity for adjustments. The fair value of the tangible assets and liabilities for each applicable acquisition at the acquisition date approximated their carrying values. The fair value of expiration lists was established using the excess earnings method, which is an income approach based on estimated financial projections developed by management for each acquired entity using market participant assumptions. Revenue growth and attrition rates generally ranged from 2.0% to 3.0% and 5.0% to 11.5% for our 2014 acquisitions, respectively, for which a valuation was performed. We estimate the fair value as the present value of the benefits anticipated from ownership of the subject customer list in excess of returns required on the investment in contributory assets necessary to realize those benefits. The rate used to discount the net benefits was based on a risk-adjusted rate that takes into consideration market-based rates of return and reflects the risk of the asset relative to the acquired business. These discount rates generally ranged from 10.5% to 15.0% for our 2014 acquisitions, for which a valuation was performed. The fair value of non-compete agreements was established using the profit differential method, which is an income approach based on estimated financial projections developed by management for the acquired company using market participant assumptions and various non-compete scenarios.
Of the $895.9 million of expiration lists, $11.9 million of non-compete agreements and $9.4 million of trade names related to the 2014 acquisitions, $679.3 million, $9.9 million and $7.1 million, respectively, is not expected to be deductible for income tax purposes. Accordingly, we recorded a deferred tax liability of $173.9 million, and a corresponding amount of goodwill, in 2014 related to the nondeductible amortizable intangible assets.

Our consolidated financial statements for the year ended December 31, 2014 include the operations of the acquired entities from their respective acquisition dates. The following is a summary of the unaudited pro forma historical results, as if these entities had been acquired at January 1, 2013 (in millions, except per share data):


		Year Ended December 31,
		2014				2013
Total revenues		$	4,984.20			$	3,968.10
Net earnings			316.1				298.4
Basic earnings per share			1.94				1.91
Diluted earnings per share			1.93				1.89
The unaudited pro forma results above have been prepared for comparative purposes only and do not purport to be indicative of the results of operations which actually would have resulted had these acquisitions occurred at January 1, 2013, nor are they necessarily indicative of future operating results. Annualized revenues of entities acquired in 2014 totaled approximately $761.2 million. Total revenues and net earnings recorded in our consolidated statement of earnings for 2014 related to the 2014 acquisitions in the aggregate were $413.0 million and $37.8 million, respectively.

4	Other Current Assets
Major classes of other current assets consist of the following (in millions):


		December 31,
		2014				2013
Premium finance advances and loans		$	232.6			$	2.3
Accrued supplemental, direct bill and other receivables			156.3				69
Refined coal production related receivables			103.5				56.6
Deferred income taxes - current			102.2				84.9
Prepaid expenses			72.1				48.5

Total other current assets		$	666.7			$	261.3

The premium finance loans represent short-term loans which we make to many of our brokerage related clients and other non-brokerage clients to finance their premiums paid to insurance carriers. These premium finance loans are primarily generated by the Crombie/OAMPS operations which were acquired on June 16, 2014. Financing receivables are carried at amortized cost. Given that these receivables are collateralized, carry a fairly rapid delinquency period of only seven days post payment date, and that contractually the underlying insurance policies will be cancelled within one month of the payment due date, there historically has not been any risk of receiving payment and therefore we do not maintain any significant allowance for losses against this balance.

Fixed_Assets

Fixed Assets	12 Months Ended
Fixed Assets	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Fixed Assets	5	Fixed Assets
	Major classes of fixed assets consist of the following (in millions):


			December 31,
			2014			2013
	Office equipment		$	23		$	16.3
	Furniture and fixtures			89.6			78.3
	Computer equipment			133.9			117.2
	Leasehold improvements			102.9			77.9
	Software			187.8			147.6
	Other			11.5			8.5

				548.7			445.8
	Accumulated depreciation			(353.3	)		(285.4	)

	Net fixed assets		$	195.4		$	160.4

Intangible_Assets

Intangible Assets	12 Months Ended
Intangible Assets	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	6	Intangible Assets
	The carrying amount of goodwill at December 31, 2014 and 2013 allocated by domestic and foreign operations is as follows (in millions):


			Brokerage			Risk			Corporate		Total
			Brokerage			Management			Corporate		Total
	At December 31, 2014
	United States		$	1,652.60		$	20.2		$	—	$	1,672.80
	United Kingdom			818.7			1.9			—		820.6
	Canada			318.5			—			—		318.5
	Australia			336.8			—			—		336.8
	Other foreign, principally New Zealand			300.9			—			—		300.9

	Total goodwill - net		$	3,427.50		$	22.1		$	—	$	3,449.60

	At December 31, 2013
	United States		$	1,449.60		$	20.2		$	—	$	1,469.80
	United Kingdom			582.8			2.1			—		584.9
	Canada			26.8			—			—		26.8
	Australia			37.1			—			—		37.1
	Other foreign			26.6			—			—		26.6

	Total goodwill - net		$	2,122.90		$	22.3		$	—	$	2,145.20

	The changes in the carrying amount of goodwill for 2014 and 2013 are as follows (in millions):


			Brokerage			Risk			Corporate		Total
			Brokerage			Management			Corporate		Total
	Balance as of January 1, 2013		$	1,451.40		$	21.3		$	—	$	1,472.70
	Goodwill acquired during the year			664.1			0.9			—		665
	Goodwill adjustments related to appraisals and other acquisition adjustments			3.3			—			—		3.3
	Foreign currency translation adjustments during the year			4.1			0.1			—		4.2

	Balance as of December 31, 2013			2,122.90			22.3			—		2,145.20
	Goodwill acquired during the year			1,448.30			—			—		1,448.30
	Goodwill adjustments related to appraisals and other acquisition adjustments			(8.8	)		—			—		(8.8	)
	Goodwill written-off related to sales of business			(0.6	)		—			—		(0.6	)
	Foreign currency translation adjustments during the year			(134.3	)		(0.2	)		—		(134.5	)

	Balance as of December 31, 2014		$	3,427.50		$	22.1		$	—	$	3,449.60

	Major classes of amortizable intangible assets consist of the following (in millions):


			December 31,
			2014			2013
	Expiration lists		$	2,461.90		$	1,563.50
	Accumulated amortization – expiration lists			(719.3	)		(511.3	)

				1,742.60			1,052.20

	Non-compete agreements			43.2			37.3
	Accumulated amortization – non-compete agreements			(29.5	)		(25.9	)

				13.7			11.4

	Trade names			29.7			22.1
	Accumulated amortization – trade names			(10.0	)		(6.9	)

				19.7			15.2

	Net amortizable assets		$	1,776.00		$	1,078.80


Estimated aggregate amortization expense for each of the next five years is as follows (in millions):


2015		$	214.6
2016			208.5
2017			198.7
2018			187.2
2019			173.6

Total		$	982.6

Credit_and_Other_Debt_Agreemen

Credit and Other Debt Agreements	12 Months Ended
Credit and Other Debt Agreements	Dec. 31, 2014
Debt Disclosure [Abstract]
Credit and Other Debt Agreements	7	Credit and Other Debt Agreements
	The following is a summary of our corporate and other debt (in millions):


			December 31,
			2014		2013
	Note Purchase Agreements:
	Semi-annual payments of interest, fixed rate of 6.26%, balloon due 2014		$	—	$	100
	Semi-annual payments of interest, fixed rate of 6.44%, balloon due 2017			300		300
	Semi-annual payments of interest, fixed rate of 2.80%, balloon due 2018			50		—
	Semi-annual payments of interest, fixed rate of 3.20%, balloon due 2019			50		—
	Semi-annual payments of interest, fixed rate of 5.85%, $50 million due in 2016, 2018 and 2019			150		150
	Semi-annual payments of interest, fixed rate of 3.99%, balloon due 2020			50		50
	Semi-annual payments of interest, fixed rate of 3.48%, balloon due 2020			50		—
	Semi-annual payments of interest, fixed rate of 5.18%, balloon due 2021			75		75
	Semi-annual payments of interest, fixed rate of 3.69%, balloon due 2022			200		200
	Semi-annual payments of interest, fixed rate of 5.49%, balloon due 2023			50		50
	Semi-annual payments of interest, fixed rate of 4.13%, balloon due 2023			200		—
	Semi-annual payments of interest, fixed rate of 4.58%, balloon due 2024			325		—
	Semi-annual payments of interest, fixed rate of 4.31%, balloon due 2025			200		—
	Semi-annual payments of interest, fixed rate of 4.73%, balloon due 2026			175		—
	Semi-annual payments of interest, fixed rate of 4.36%, balloon due 2026			150		—
	Semi-annual payments of interest, fixed rate of 4.98%, balloon due 2029			100		—

	Total Note Purchase Agreements			2,125.00		925

	Credit Agreement:
	Periodic payments of interest and principal, prime or LIBOR plus up to 1.45%, expires September 19, 2018			140		530.5

	Premium Financing Debt Facility - expires June 15, 2016:
	Periodic payments of interest and principal, Interbank rates plus 1.65% for Facility B; plus 0.85% for Facilities C and D
	Facility B
	AUD denominated tranche			95		—
	NZD denominated tranche			17.8		—
	Facility C and D
	AUD denominated tranche			7.7		—
	NZD denominated tranche			7.4		—

	Total Premium Financing Debt Facility			127.9		—

	Total corporate and other debt		$	2,392.90	$	1,455.50

	Note Purchase Agreements - We are a party to an amended and restated note purchase agreement dated December 19, 2007, with certain accredited institutional investors, pursuant to which we issued and sold $300.0 million in aggregate principal amount of our 6.44% Senior Notes, Series B, due August 3, 2017, in a private placement. These notes require semi-annual payments of interest that are due in February and August of each year.

	We are a party to a note purchase agreement dated November 30, 2009, with certain accredited institutional investors, pursuant to which we issued and sold $150.0 million in aggregate principal amount of our 5.85% Senior Notes, Series C, due in three equal installments on November 30, 2016, November 30, 2018 and November 30, 2019, in a private placement. These notes require semi-annual payments of interest that are due in May and November of each year.
	We are a party to a note purchase agreement dated February 10, 2011, with certain accredited institutional investors, pursuant to which we issued and sold $75.0 million in aggregate principal amount of our 5.18% Senior Notes, Series D, due February 10, 2021 and $50.0 million in aggregate principal amount of our 5.49% Senior Notes, Series E, due February 10, 2023, in a private placement. These notes require semi-annual payments of interest that are due in February and August of each year.
	We are a party to a note purchase agreement dated July 10, 2012, with certain accredited institutional investors, pursuant to which we issued and sold $50.0 million in aggregate principal amount of our 3.99% Senior Notes, Series F, due July 10, 2020, in a private placement. These notes require semi-annual payments of interest that are due in January and July of each year.
	We are a party to a note purchase agreement dated June 14, 2013, with certain accredited institutional investors, pursuant to which we issued and sold $200.0 million in aggregate principal amount of our 3.69% Senior Notes, Series G, due June 14, 2022, in a private placement. These notes require semi-annual payments of interest that are due in June and December of each year.
	We are a party to a note purchase agreement dated December 20, 2013, with certain accredited investors, pursuant to which we issued and sold $325.0 million in aggregate principle amount of our 4.58% Senior Notes, Series H, due February 27, 2024, $175.0 million in aggregate principle amount of our 4.73% Senior Notes, Series I, due February 27, 2026 and $100.0 million in aggregate principle amount of our 4.98% Senior Notes, Series J, due February 27, 2029. These notes will require semi-annual payments of interest that due in February and August of each year. The funding of this note purchase agreement occurred on February 27, 2014. We incurred approximately $1.4 million of debt acquisition costs that was capitalized and will be amortized on a pro rata basis over the life of the debt.
	We are a party to a note purchase agreement dated June 24, 2014, with certain accredited institutional investors, pursuant to which we issued and sold $50.0 million in aggregate principal amount of our 2.80% Senior Notes, Series K, due June 24, 2018, $50.0 million in aggregate principal amount of our 3.20% Senior Notes, Series L, due June 24, 2019, $50.0 million in aggregate principal amount of our 3.48% Senior Notes, Series M, due June 24, 2020, $200.0 million in aggregate principal amount of our 4.13% Senior Notes, Series N, due June 24, 2023, $200.0 million in aggregate principal amount of our 4.31% Senior Notes, Series O, due June 24, 2025 and $150.0 million in aggregate principal amount of our 4.36% Senior Notes, Series P, due June 24, 2026. These notes require semi-annual payments of interest that are due in June and December of each year. We incurred approximately $2.6 million of debt acquisition costs that was capitalized and will be amortized on a pro rata basis over the life of the debt.
	Under the terms of the note purchase agreements described above, we may redeem the notes at any time, in whole or in part, at 100% of the principal amount of such notes being redeemed, together with accrued and unpaid interest and a “make-whole amount”. The “make-whole amount” is derived from a net present value computation of the remaining scheduled payments of principal and interest using a discount rate based on the U.S. Treasury yield plus 0.5% and is designed to compensate the purchasers of the notes for their investment risk in the event prevailing interest rates at the time of prepayment are less favorable than the interest rates under the notes. We do not currently intend to prepay any of the notes.
	The note purchase agreements described above contain customary provisions for transactions of this type, including representations and warranties regarding us and our subsidiaries and various financial covenants, including covenants that require us to maintain specified financial ratios. We were in compliance with these covenants as of December 31, 2014. The note purchase agreements also provide customary events of default, generally with corresponding grace periods, including, without limitation, payment defaults with respect to the notes, covenant defaults, cross-defaults to other agreements evidencing our or our subsidiaries’ indebtedness, certain judgments against us or our subsidiaries and events of bankruptcy involving us or our material subsidiaries.
	The notes issued under the note purchase agreement are senior unsecured obligations of ours and rank equal in right of payment with our Credit Agreement discussed below.
	Credit Agreement - On September 19, 2013, we entered into a $600.0 million unsecured multicurrency credit agreement (which we refer to as the Credit Agreement), which expires on September 19, 2018, with a group of fifteen financial institutions. The Credit Agreement provides for a revolving credit commitment of up to $600.0 million, of which up to $75.0 million may be used for issuances of standby or commercial letters of credit and up to $50.0 million may be used for the making of swing loans, as defined in the Credit Agreement. We may from time to time request, subject to certain conditions, an increase in the revolving credit commitment up to a maximum aggregate revolving credit commitment of $850.0 million.
	The Credit Agreement provides that we may elect that each borrowing in U.S. dollars be either base rate loans or Eurocurrency loans, as defined in the Credit Agreement. All loans denominated in currencies other than U.S. dollars will be Eurocurrency loans. Interest rates on base rate loans and outstanding drawings on letters of credit in U.S. dollars under the Credit Agreement are based on the base rate, as defined in the Credit Agreement. Interest rates on Eurocurrency loans or outstanding drawings on letters of credit in currencies other than U.S. dollars are based on an adjusted London Interbank Offered Rate (which we refer to as LIBOR), as defined in the Credit Agreement, plus a margin of 0.85%, 0.95%, 1.05%, 1.25% or 1.45%, depending on the financial leverage ratio we maintain. Interest rates on swing loans are based, at our election, on either the base rate, as defined in the Credit Agreement, or such alternate rate as may be quoted by the lead lender. The annual facility fee related to the Credit Agreement is 0.15%, 0.175%, 0.20%, 0.25% or 0.30% of the used and unused portions of the revolving credit commitment, depending on the financial leverage ratio we maintain. In connection with entering into the Credit Agreement, we incurred approximately $2.1 million of debt acquisition costs that were capitalized and will be amortized on a pro rata basis over the term of the Credit Agreement.
	The terms of the Credit Agreement include various financial covenants, including covenants that require us to maintain specified financial leverage ratios. We were in compliance with these covenants as of December 31, 2014. The Credit Agreement also includes customary provisions for transactions of this type, including events of default, with corresponding grace periods, cross-defaults to other agreements evidencing our indebtedness.
	At December 31, 2014, $22.6 million of letters of credit (for which we had $9.7 million of liabilities recorded at December 31, 2014) were outstanding under the Credit Agreement. See Note 14 to our consolidated financial statements for a discussion of the letters of credit. There were $140.0 million of borrowings outstanding under the Credit Agreement at December 31, 2014. Accordingly, at December 31, 2014, $437.4 million remained available for potential borrowings, of which $52.4 million was available for additional letters of credit.
	Premium Financing Debt Facility - On June 16, 2014 we entered into a Syndicated Facility Agreement, revolving loan facility, which we refer to as the Premium Financing Debt Facility, that provides funding for the three acquired Australian (AU) and New Zealand (NZ) premium finance subsidiaries. See Note 3 “Business Combinations.” The Premium Financing Debt Facility is comprised of: (i) Facility B is separate AU$150.0 million and NZ$35.0 million tranches, (ii) Facility C is an AU$25.0 million equivalent multi-currency overdraft tranche and (iii) Facility D is a NZ$15.0 million equivalent multi-currency overdraft tranche. The Premium Financing Debt Facility expires June 15, 2016.
	The interest rates on Facility B are Interbank rates, which vary by tranche, duration and currency, plus a margin of 1.65%. The interest rates on Facilities C and D are 30 day Interbank rates, plus a margin of 0.85%. The annual fee for Facility B is 0.7425% of the undrawn commitments for the two tranches of the facility. The annual fee for Facilities C and D is 0.80% of the total commitments of the facilities. In connection with entering into the Premium Financing Debt Facility, we incurred an upfront fee of 0.30% of the principal amount of the committed facilities.
	The terms of our Premium Financing Debt Facility include various financial covenants, including covenants that require us to maintain specified financial ratios. We were in compliance with these covenants as of December 31, 2014. The Premium Financing Debt Facility also includes customary provisions for transactions of this type, including events of default, with corresponding grace periods and cross-defaults to other agreements evidencing our indebtedness. Facilities B, C and D are secured by the premium finance receivables of the Australian and New Zealand premium finance subsidiaries.
	At December 31, 2014, AU$117.0 million and NZ$23.0 million of borrowings were outstanding under Facility B, AU$9.4 million of borrowings were outstanding under Facility C and NZ$9.6 million of borrowings were outstanding under Facility D. Accordingly, as of December 31, 2014, AU$33.0 million and NZ$12.0 million remained available for potential borrowing under Facility B, and AU$15.6 million and NZ$5.4 million under Facilities C and D, respectively.
	See Note 13 to these unaudited consolidated financial statements for additional discussion on our contractual obligations and commitments as of December 31, 2014.
	The aggregate estimated fair value of the $2,125.0 million in debt under the note purchase agreements at December 31, 2014 was $2,281.0 million due to the long-term duration and fixed interest rates associated with these debt obligations. No active or observable market exists for our private long-term debt. Therefore, the estimated fair value of this debt is based on discounted future cash flows, which is a Level 3 fair value measurement, using current interest rates available for debt with similar terms and remaining maturities. The estimated fair value of this debt is based on the income valuation approach, which is a valuation technique that converts future amounts (for example, cash flows or income and expenses) to a single current (that is, discounted) amount. The fair value measurement is determined on the basis of the value indicated by current market expectations about those future amounts. Because our debt issuances generate a measurable income stream for each lender, the income approach was deemed to be an appropriate methodology for valuing the private placement long-term debt. The methodology used calculated the original deal spread at the time of each debt issuance, which was equal to the difference between the yield of each issuance (the coupon rate) and the equivalent benchmark treasury yield at that time. The market spread as of the valuation date was calculated, which is equal to the difference between an index for investment grade insurers and the equivalent benchmark treasury yield today. An implied premium or discount to the par value of each debt issuance based on the difference between the origination deal spread and market as of the valuation date was then calculated. The index we relied on to represent investment graded insurers was the Bloomberg Valuation Services (BVAL) U.S. Insurers BBB index. This index is comprised primarily of insurance brokerage firms and was representative of the industry in which we operate. For the purposes of our analysis, the average BBB rate was assumed to be the appropriate borrowing rate for us based on the our current credit rating. The estimated fair value of the $140.0 million of borrowings outstanding under our Credit Agreement approximate their carrying value due to their short-term duration and variable interest rates. The estimated fair value of the $127.9 million of borrowings outstanding under our Premium Financing Debt Facility approximates their carrying value due to their short-term duration and variable interest rates.

Earnings_per_Share

Earnings per Share	12 Months Ended
Earnings per Share	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings per Share	8	Earnings per Share
	The following table sets forth the computation of basic and diluted net earnings per share (in millions, except per share data):


			Year Ended December 31,
			2014		2013		2012
	Net earnings		$	303.4	$	268.6	$	195

	Weighted average number of common shares outstanding			152.9		128.9		121
	Dilutive effect of stock options using the treasury stock method			1.4		1.6		1.5

	Weighted average number of common and common equivalent shares outstanding			154.3		130.5		122.5

	Basic net earnings per share		$	1.98	$	2.08	$	1.61

	Diluted net earnings per share:		$	1.97	$	2.06	$	1.59

	Options to purchase 1.6 million, 1.3 million and 1.1 million shares of our common stock were outstanding at December 31, 2014, 2013 and 2012, respectively, but were not included in the computation of the dilutive effect of stock options for the year then ended. These stock options were excluded from the computation because the options’ exercise prices were greater than the average market price of our common shares during the respective period and, therefore, would be anti-dilutive to earnings per share under the treasury stock method.

Stock_Option_Plans

Stock Option Plans	12 Months Ended
Stock Option Plans	Dec. 31, 2014
Text Block [Abstract]
Stock Option Plans	9	Stock Option Plans
	Long-Term Incentive Plan
	On May 13, 2014, our stockholders approved the Arthur J. Gallagher 2014 Long-Term Incentive Plan (which we refer to as the LTIP), which replaced our previous stockholder-approved Arthur J. Gallagher & Co. 2011 Long-Term Incentive Plan (which we refer to as the 2011 LTIP). The LTIP term began May 13, 2014 and terminates on the date of the annual meeting of stockholders in 2021, unless terminated earlier by our board of directors. All of our officers, employees and non-employee directors are eligible to receive awards under the LTIP. The compensation committee of our board of directors determines the participants under the LTIP. The LTIP provides for non-qualified and incentive stock options, stock appreciation rights, restricted stock, restricted stock units and performance units, any or all of which may be made contingent upon the achievement of performance criteria. A stock appreciation right entitles the holder to receive, upon exercise and subject to withholding taxes, cash or shares of our common stock (which may be restricted stock) with a value equal to the difference between the fair market value of our common stock on the exercise date and the base price of the stock appreciation right. Subject to the LTIP limits, the compensation committee has the discretionary authority to determine the size of an award.
	Shares of our common stock available for issuance under the LTIP include authorized and unissued shares of common stock or authorized and issued shares of common stock reacquired and held as treasury shares or otherwise, or a combination thereof. The number of available shares will be reduced by the aggregate number of shares that become subject to outstanding awards granted under the LTIP. To the extent that shares subject to an outstanding award granted under either the LTIP or the 2011 LTIP are not issued or delivered by reason of the expiration, termination, cancellation or forfeiture of such award or by reason of the settlement of such award in cash, then such shares will again be available for grant under the LTIP. Shares withheld to satisfy tax withholding requirements upon the vesting of awards other than stock options and stock appreciation rights will also be available for grant under the LTIP. Shares that are subject to a stock appreciation right and were not issued upon the net settlement or net exercise of such stock appreciation right, shares that are used to pay the exercise price of an option, delivered to or withheld by us to pay withholding taxes related to stock options or stock appreciation rights, and shares that are purchased on the open market with the proceeds of an option exercise, may not again be made available for issuance.
	The maximum number of shares available under the LTIP for restricted stock, restricted stock unit awards and performance unit awards settled with stock (i.e., all awards other than stock options and stock appreciation rights) is 2.0 million as of December 31, 2014. To the extent necessary to be qualified performance-based compensation under Section 162(m) of the Internal Revenue Code (which we refer to as the IRC); (i) the maximum number of shares with respect to which options or stock appreciation rights or a combination thereof that may be granted during any fiscal year to any person is 200,000; (ii) the maximum number of shares with respect to which performance-based restricted stock or restricted stock units that may be granted during any fiscal year to any person is 100,000; and (iii) the maximum amount that may be payable with respect to cash-settled performance units granted during any fiscal year to any person is $5.0 million; and (iv) the maximum number of shares with respect to which stock-settled performance units may be granted during any fiscal year to any person is 100,000.

	The LTIP provides for the grant of stock options, which may be either tax-qualified incentive stock options or non-qualified options and stock appreciation rights. The compensation committee determines the period for the exercise of a non-qualified stock option, tax-qualified incentive stock option or stock appreciation right, provided that no option can be exercised later than seven years after its date of grant. The exercise price of a non-qualified stock option or tax-qualified incentive stock option and the base price of a stock appreciation right cannot be less than 100% of the fair market value of a share of our common stock on the date of grant, provided that the base price of a stock appreciation right granted in tandem with an option will be the exercise price of the related option.
	Upon exercise, the option exercise price may be paid in cash, by the delivery of previously owned shares of our common stock, through a net-exercise arrangement, or through a broker-assisted cashless exercise arrangement. The compensation committee determines all of the terms relating to the exercise, cancellation or other disposition of an option or stock appreciation right upon a termination of employment, whether by reason of disability, retirement, death or any other reason. Stock option and stock appreciation right awards under the LTIP are non-transferable.
	In addition to any discretionary stock options, each non-employee director is eligible under the LTIP to receive all or part of his or her annual retainer in the form of stock options, in lieu of cash. An option granted in lieu of a cash retainer will have an exercise price per share equal to the fair market value of a share of our common stock on the date the option is granted. The number of shares of common stock subject to each such option grant has a fair market value as of the date of the grant equal to a multiple of the forgone retainer. The board of directors determines the multiple from time to time based on the Black-Scholes model. We calculate the number of shares by multiplying the forgone cash retainer amount by the designated multiple, and then dividing that amount by the value of a share of common stock on the date of grant. Such options become exercisable in equal installments over the four quarters succeeding the date of grant and remain exercisable until the seventh anniversary of the date of grant.
	On March 12, 2014, the compensation committee granted 1,923,000 options to our officers and key employees that become exercisable at the rate of 34%, 33% and 33% on the anniversary date of the grant in 2017, 2018 and 2019, respectively. On March 13, 2013, the compensation committee granted 1,665,000 options to our officers and key employees that become exercisable at the rate of 34%, 33% and 33% on the anniversary date of the grant in 2016, 2017 and 2018, respectively. On March 16, 2012, the compensation committee granted 1,355,000 options to our officers and key employees that become exercisable at the rate of 34%, 33% and 33% on the anniversary date of the grant in 2015, 2016 and 2017, respectively. The 2014, 2013 and 2012 options expire seven years from the date of grant, or earlier in the event of termination of the employee. For certain of our executive officers age 55 or older, stock options awarded in 2014 and 2013 are no longer subject to forfeiture upon such officers’ departure from the company after two years from the date of grant.
	Prior Stock Option Plans
	Prior to 2009, we issued stock options under four stock option-based employee compensation plans. In May 2008, all of these plans expired. Under the expired plans, we granted both incentive and nonqualified stock options to our officers and key employees. Most options granted under the incentive plan prior to 2007 become exercisable at the rate of 10% per year beginning the calendar year after the date of grant. Most options granted under the nonqualified plan prior to 2007 become exercisable at the rate of 10% per year beginning the calendar year after the date of grant or provided for accelerated vesting to 100% in the event of death, disability or retirement (if the retirement eligible age requirement is met). Options granted prior to 2009 expire ten years from the date of grant, or earlier in the event of termination of the employee (if the retirement eligible age requirement is not met).
	Other Information
	All of our stock option plans provide for the immediate vesting of all outstanding stock option grants in the event of a change in control of our company, as defined in the applicable plan documents.
	During 2014, 2013 and 2012, we recognized $9.5 million, $7.7 million and $7.2 million, respectively, of compensation expense related to our stock option grants.
	For purposes of expense recognition in 2014, 2013 and 2012, the estimated fair values of the stock option grants are amortized to expense over the options’ vesting period. We estimated the fair value of stock options at the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:


			Year Ended December 31,
			2014				2013			2012
	Expected dividend yield			3	%			3.5	%		4	%
	Expected risk-free interest rate			1.8	%			1.2	%		1.2	%
	Volatility			28.9	%			29.6	%		26.9	%
	Expected life (in years)			5.5				6			5

	Option valuation models require the input of highly subjective assumptions including the expected stock price volatility. The Black-Scholes option pricing model was developed for use in estimating the fair value of traded options which have no vesting restrictions and are fully transferable. Because our employee and director stock options have characteristics significantly different from those of traded options, and because changes in the selective input assumptions can materially affect the fair value estimate, in management’s opinion, the existing models do not necessarily provide a reliable single measure of the fair value of our employee and non-employee director stock options. The weighted average fair value per option for all options granted during 2014, 2013 and 2012, as determined on the grant date using the Black-Scholes option pricing model, was $9.66, $7.51 and $5.49, respectively.
	The following is a summary of our stock option activity and related information for 2014, 2013 and 2012 (in millions, except exercise price and year data):


	Year Ended December 31, 2014		Shares				Weighted			Weighted				Aggregate
			Under				Average			Average				Intrinsic
			Option				Exercise			Remaining				Value
							Price			Contractual
										Term
										(in years)
	Beginning balance			8.3			$	31.35
	Granted			1.9				46.86
	Exercised			(1.7	)			28.8
	Forfeited or canceled			(0.1	)			28.36

	Ending balance			8.4			$	35.49			3.96			$	97.2

	Exercisable at end of year			2.6			$	26.91			1.87			$	52.8

	Ending vested and expected to vest			8.3			$	35.38			3.93			$	96.6

	Year Ended December 31, 2013
	Beginning balance			9			$	28.8
	Granted			1.7				39.17
	Exercised			(2.3	)			27.11
	Forfeited or canceled			(0.1	)			26.01

	Ending balance			8.3			$	31.35			3.62			$	129.4

	Exercisable at end of year			3.8			$	27.64			2.15			$	72.5

	Ending vested and expected to vest			8.2			$	31.28			3.59			$	128.3

	Year Ended December 31, 2012
	Beginning balance			10.6			$	27.2
	Granted			1.4				35.71
	Exercised			(2.8	)			26.14
	Forfeited or canceled			(0.2	)			29.46

Ending balance			9			$	28.8			3.41			$	53.9

Exercisable at end of year			5.1			$	27.5			2.52			$	36.3

Ending vested and expected to vest			8.9			$	28.76			3.39			$	53.8

Options with respect to 9.3 million shares (less any shares of restricted stock issued under the LTIP—see Note 11 to our consolidated financial statements) were available for grant under the LTIP at December 31, 2014.
The total intrinsic value of options exercised during 2014, 2013 and 2012 amounted to $30.5 million, $32.0 million and $26.0 million, respectively. At December 31, 2014, we had approximately $28.8 million of total unrecognized compensation cost related to nonvested options. We expect to recognize that cost over a weighted average period of approximately four years.

Other information regarding stock options outstanding and exercisable at December 31, 2014 is summarized as follows (in millions, except exercise price and year data):


				Options Outstanding											Options Exercisable
Range of Exercise Prices				Number				Weighted			Weighted				Number		Weighted
				Outstanding				Average			Average				Exercisable		Average
								Remaining			Exercise						Exercise
								Contractual			Price						Price
								Term
								(in years)
$	21.28 - $ 27.25				2.3				1.59		$	25.78				1.9	$	25.76
	27.35 - 35.71				2.5				3.59			33.18				0.7		29.83
	35.95 - 46.16				1.7				5.2			39.19				—		—
	46.87 - 46.87				1.9				6.19			46.87				—		—

$	21.28 - $ 46.87				8.4				3.96		$	35.49				2.6	$	26.91

Deferred_Compensation

Deferred Compensation	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Deferred Compensation	10	Deferred Compensation
	We have a Deferred Equity Participation Plan, (which we refer to as the Age 62 Plan), which is a non-qualified plan that generally provides for distributions to certain of our key executives when they reach 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. Under the provisions of the Age 62 plan, we typically contribute cash in an amount approved by the compensation committee to a rabbi trust on behalf of the executives participating in the Age 62 plan, and instruct the trustee to acquire a specified number of shares of our common stock on the open market or in privately negotiated transactions based on participant elections. Distributions under the Age 62 plan may not normally be made until the participant reaches 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) and are subject to forfeiture in the event of voluntary termination of employment prior to then. All contributions to the plan deemed to be invested in shares of our common stock are distributed in the form of our common stock and all other distributions are paid in cash.
	Our common stock that is issued to or purchased by the rabbi trust as a contribution under the Age 62 Plan is valued at historical cost, which equals its fair market value at the date of grant or date of purchase. When common stock is issued, we record an unearned deferred compensation obligation as a reduction of capital in excess of par value in the accompanying consolidated balance sheet, which is amortized to compensation expense ratably over the vesting period of the participants. Future changes in the fair market value of our common stock owed to the participants do not have any impact on the amounts recorded in our consolidated financial statements.
	In the first quarter of each of 2014, 2013 and 2012, the compensation committee approved $9.2 million, $8.0 million and $7.3 million, respectively, of awards in the aggregate to certain key executives under the Age 62 Plan that were contributed to the rabbi trust in the second quarter of 2013 and the first quarters of 2014 and 2012. We contributed cash to the rabbi trust and instructed the trustee to acquire a specified number of shares of our common stock on the open market to fund these 2014, 2013 and 2012 awards. In the second quarter of 2013, we instructed the trustee for the Age 62 Plan to liquidate all investments held under the Age 62 Plan, other than our common stock, and use the proceeds to purchase additional shares of our common stock on the open market. As a result, the Age 62 Plan sold all of the funded cash award assets and purchased 1.2 million shares of our common stock at an aggregate cost of $52.4 million during the second quarter of 2013. During 2014, 2013 and 2012, we charged $7.4 million, $7.2 million and $5.4 million, respectively, to compensation expense related to these awards.
	At December 31, 2014 and 2013, we recorded $28.2 million (related to 1.9 million shares) and $26.3 million (related to 2.1 million shares), respectively, of unearned deferred compensation as an reduction of capital in excess of par value in the accompanying consolidated balance sheet. The total intrinsic value of our unvested equity based awards under the plan at December 31, 2014 and 2013 was $89.1 million and $96.4 million, respectively. During 2014, 2013 and 2012, cash and equity awards with an aggregate fair value of $18.8 million, $1.4 million and $0.7 million, respectively, were vested and distributed to employees under the Age 62 plan.
	We have a Deferred Cash Participation Plan (which we refer to as the DCPP), which is a non-qualified deferred compensation plan for certain key employees, other than executive officers, that generally provides for distributions no sooner than five years from the date of awards, with full vesting after thirteen months from the date of awards. Under the provisions of the DCPP, we typically contribute cash in an amount approved by compensation committee to the rabbi trust on behalf of the executives participating in the DCPP, and instruct the trustee to acquire a specified number of shares of our common stock on the open market or in privately negotiated transactions based on participant elections. In the first quarter of each of 2014 and 2013, the compensation committee approved $2.9 million and $2.7 million, respectively, of awards in the aggregate to certain key executives under the DCPP that were contributed to the rabbi trust in first quarter 2014 and second quarter 2013. During 2014 we charged $2.8 million to compensation expense related to these awards. During 2014, cash and equity awards with an aggregate fair value of $0.1 million were vested and distributed to executives under the DCPP.

Restricted_Stock_Performance_S

Restricted Stock, Performance Share and Cash Awards

12 Months Ended

Dec. 31, 2014

Text Block [Abstract]

Restricted Stock, Performance Share and Cash Awards

Restricted Stock Awards

As discussed in Note 9 to our consolidated financial statements, on May 13, 2014, our stockholders approved the LTIP, which replaced our previous stockholder-approved 2011 LTIP. The LTIP provides for the grant of a stock award either as restricted stock or as restricted stock units. In either case, the compensation committee may determine that the award will be subject to the attainment of performance measures over an established performance period. Stock awards and the related dividend equivalents are non-transferable and subject to forfeiture if the holder does not remain continuously employed with us during the applicable restriction period or, in the case of a performance-based award, if applicable performance measures are not attained. The compensation committee will determine all of the terms relating to the satisfaction of performance measures and the termination of a restriction period, or the forfeiture and cancellation of a restricted stock award upon a termination of employment, whether by reason of disability, retirement, death or any other reason. The compensation committee may grant unrestricted shares of common stock or units representing the right to receive shares of common stock to employees who have attained age 62.

The agreements awarding restricted stock units under the LTIP will specify whether such awards may be settled in shares of our common stock, cash or a combination of shares and cash and whether the holder will be entitled to receive dividend equivalents, on a current or deferred basis, with respect to such award. Prior to the settlement of a restricted stock unit, the holder of a restricted stock unit will have no rights as a stockholder of the company. The maximum number of shares available under the LTIP for restricted stock, restricted stock units and performance unit awards settled with stock (i.e., all awards other than stock options and stock appreciation rights) is 2.0 million. At December 31, 2014, 2.0 million shares were available for grant under the LTIP for such awards.

Prior to May 12, 2009, we had a restricted stock plan for our directors, officers and certain other employees, which was superseded by the 2009 LTIP. Under the provisions of that plan, we were authorized to issue 4.0 million restricted shares or related stock units of our common stock. The compensation committee was responsible for the administration of the plan. Each award granted under the plan represented a right of the holder of the award to receive shares of our common stock, cash or a combination of shares and cash, subject to the holder’s continued employment with us for a period of time after the date the award is granted. The compensation committee determined each recipient of an award under the plan, the number of shares of common stock subject to such award and the period of continued employment required for the vesting of such award.

In 2014, 2013 and 2012, we granted 342,850, 369,975 and 361,400 units, respectively, of our common stock to employees under the LTIP, with an aggregate fair value of $16.0 million, $14.6 million and $12.9 million, respectively, at the date of grant.

The 2014, 2013 and 2012 restricted stock awards (consisting of restricted stock or restricted stock units) vest as follows: 323,550 shares granted in first quarter 2014, 345,000 shares granted in first quarter 2013 and 332,000 shares granted in first quarter 2012, vest in full based on continued employment through March 12, 2018, March 13, 2017 and March 16, 2016, respectively, while the other 2014, 2013 and 2012 restricted stock awards generally vest in full based on continued employment through the vesting period on the anniversary date of the grant. In the third quarter of 2014, we granted 33,741 restricted stock units to employees with an aggregate fair value of $1.5 million at the date of grant. These grants vest at the rate of 34%, 33% and 33% on the anniversary date of the grant in 2015, 2016 and 2017, respectively from the date of grant. For certain of our executive officers age 55 or older, restricted stock units awarded in 2014 and 2013 are no longer subject to forfeiture upon such officers’ departure from the company after two years from the date of grant.

The vesting periods of the 2014, 2013 and 2012 restricted stock awards are as follows (in actual shares):

Shares Granted

Vesting Period

2014

2013

2012

One year

19,250

19,375

20,000

Three years

33,741

—

Four years

323,550

345,000

332,000

Five years

—

5,600

9,400

Total shares granted

376,541

369,975

361,400

We account for restricted stock awards at historical cost, which equals its fair market value at the date of grant, which is amortized to compensation expense ratably over the vesting period of the participants. Future changes in the fair value of our common stock that is owed to the participants do not have any impact on the amounts recorded in our consolidated financial statements. During 2014, 2013 and 2012, we charged $12.7 million, $9.8 million and $7.1 million, respectively, to compensation expense related to restricted stock awards granted in 2006 through 2014. The total intrinsic value of unvested restricted stock at December 31, 2014 and 2013 was $57.3 million and $49.5 million, respectively. During 2014 and 2013, equity awards (including accrued dividends) with an aggregate fair value of $10.0 million and $8.4 million were vested and distributed to employees under this plan.

Performance Share Awards

On March 12, 2014, pursuant to the LTIP, the compensation committee approved 48,800 provisional performance share unit awards, with an aggregate fair value of $2.3 million, for future grants to our officers. Each performance unit award was equivalent to the value of one share of our common stock on the date such provisional award was approved. These awards are subject to a one-year performance period based on our financial performance and a two-year vesting period. At the discretion of the compensation committee and determined based on our performance, the eligible officer will be granted a percentage of the provisional performance unit award that equates to the EBITAC growth achieved (as specified in the applicable grant agreement). At the end of the performance period, eligible participants will be granted a number of units based on achievement of the performance goal and subject to approval by the compensation committee. Granted units for the 2014 provisional award will fully vest based on continuous employment through January 1, 2017, and will be settled in shares of our common stock on a one-for-one basis as soon as practicable in 2017. For certain of our executive officers age 55 or older, awards granted in 2014 are no longer subject to forfeiture upon such officers’ departure from the company after two years from the date of grant. If an eligible employee leaves us prior to the vesting date, the entire award will be forfeited. During 2014, we charged $0.5 million to compensation expense related to performance share unit awards granted in 2014. The total intrinsic value of unvested restricted stock at December 31, 2014 was $2.3 million.

Cash Awards

On March 12, 2014, pursuant to our Performance Unit Program (which we refer to as the Program), the compensation committee approved provisional cash awards of $10.8 million in the aggregate for future grants to our officers and key employees that are denominated in units (229,000 units in the aggregate), each of which was equivalent to the value of one share of our common stock on the date the provisional award was approved. The Program consists of a one-year performance period based on our financial performance and a two-year vesting period. At the discretion of the compensation committee and determined based on our performance, the eligible officer or key employee will be granted a percentage of the provisional cash award units that equates to the EBITAC growth achieved (as defined in the Program). At the end of the performance period, eligible participants will be granted a number of units based on achievement of the performance goal and subject to approval by the compensation committee. Granted units for the 2014 provisional award will fully vest based on continuous employment through January 1, 2017. For certain of our executive officers age 55 or older, awards granted under the Program in 2014 are no longer subject to forfeiture upon such officers’ departure from the company after two years from the date of the provisional award. The ultimate award value will be equal to the trailing twelve-month stock price on December 31, 2016, multiplied by the number of units subject to the award, but limited to between 0.5 and 1.5 times the original value of the units determined as of the grant date. The fair value of the awarded units will be paid out in cash as soon as practicable in 2017. If an eligible employee leaves us prior to the vesting date, the entire award will be forfeited. We did not recognize any compensation expense during 2014 related to the 2014 provisional award under the Program. Based on company performance for 2013, we expect to grant 220,000 units under the Program in first quarter 2015 that will fully vest on January 1, 2017.

On March 13, 2013, pursuant to the Program, the compensation committee approved the provisional cash awards of $10.5 million in the aggregate for future grants to our officers and key employees that are denominated in units (269,000 units in the aggregate), each of which was equivalent to the value of one share of our common stock on the date the provisional award was approved. Terms of the 2013 provisional award were similar to the terms of the 2014 provisional awards. Based on our performance for 2013, we granted 263,000 units under the Program in the first quarter of 2014 that will fully vest on January 1, 2016. During 2014, we charged $5.9 million to compensation expense related to these awards.

On March 16, 2012, pursuant to the Program, the compensation committee approved the provisional cash awards of $13.1 million in the aggregate for future grants to our officers and key employees that are denominated in units (368,000 units in the aggregate), each of which was equivalent to the value of one share of our common stock on the date the provisional award was approved. Terms of the 2012 provisional award were similar to the terms discussed above for the 2013 provisional award. Based on our performance for 2012, we granted 365,000 units under the Program in the first quarter of 2013 that will fully vest on January 1, 2015. During 2014 and 2013, we charged $8.4 million and $7.6 million, respectively, to compensation expense related to these awards.

On March 8, 2011, pursuant to the Program, the compensation committee approved the provisional cash awards of $14.4 million in the aggregate for future grants to our officers and key employees that are denominated in units (464,000 units in the aggregate), each of which is equivalent to the value of one share of our common stock on the date the provisional award was approved. Terms of the 2011 provisional award were similar to the terms discussed above for the 2012 provisional award. Based on our performance for 2011, we granted 432,000 units under the Program in the first quarter of 2012 that fully vested on January 1, 2014. During 2013 and 2012, we charged $10.1 million and $7.5 million, respectively, to compensation expense related to these awards. We did not recognize any compensation expense during 2014 related to the 2011 awards. During 2014, cash awards related to the 2011 provisional award with an aggregate fair value of $17.6 million (411,000 units in the aggregate) were vested and distributed to employees under the Program.

During 2012, cash awards related to the 2009 provisional award with an aggregate fair value of $26.5 million (1.1 million units in the aggregate) were vested and distributed to employees under the Program.

Retirement_Plans

Retirement Plans	12 Months Ended
Retirement Plans	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Retirement Plans	12	Retirement Plans

	We have a noncontributory defined benefit pension plan that, prior to July 1, 2005, covered substantially all of our domestic employees who had attained a specified age and one year of employment. Benefits under the plan were based on years of service and salary history. In 2005, we amended our defined benefit pension plan to freeze the accrual of future benefits for all U.S. employees, effective on July 1, 2005. Since the plan is frozen, there is no difference between the projected benefit obligation and accumulated benefit obligation at December 31, 2014 and 2013. In the table below, the service cost component represents plan administration costs that are incurred directly by the plan. A reconciliation of the beginning and ending balances of the pension benefit obligation and fair value of plan assets and the funded status of the plan is as follows (in millions):



			Year Ended December 31,
			2014				2013
	Change in pension benefit obligation:
	Benefit obligation at beginning of year		$	272.5			$	292
	Service cost			0.7				0.6
	Interest cost			12.7				11.7
	Net actuarial loss (gain)			56.8				(22.4	)
	Partial plan settlement loss			(16.7	)			—
	Benefits paid			(54.0	)			(9.4	)

	Benefit obligation at end of year		$	272			$	272.5

	Change in plan assets:
	Fair value of plan assets at beginning of year		$	254.9			$	227.4
	Actual return on plan assets			16.3				30.6
	Contributions by the company			—				6.3
	Benefits paid			(54.0	)			(9.4	)

	Fair value of plan assets at end of year		$	217.2			$	254.9

	Funded status of the plan (underfunded)		$	(54.8	)		$	(17.6	)

	Amounts recognized in the consolidated balance sheet consist of:
	Noncurrent liabilities - accrued benefit liability		$	(54.8	)		$	(17.6	)
	Accumulated other comprehensive loss - net actuarial loss			75.2				47

	Net amount included in retained earnings		$	20.4			$	29.4


	The components of the net periodic pension benefit cost for the plan and other changes in plan assets and obligations recognized in earnings and other comprehensive earnings consist of the following (in millions):



			Year Ended December 31,
			2014				2013				2012
	Net periodic pension cost (earnings):
	Service cost		$	0.7			$	0.6			$	0.4
	Interest cost on benefit obligation			12.7				11.7				11.8
	Expected return on plan assets			(18.7	)			(17.0	)			(15.2	)
	Amortization of net loss			2.3				7.9				7.2
	Settlement			12				—				—

	Net periodic benefit cost (earnings)			9				3.2				4.2

	Other changes in plan assets and obligations recognized in other comprehensive earnings:
	Net loss (gain) incurred			42.5				(36.0	)			10.6
	Settlement recognition			(12.0	)			—				—
	Amortization of net loss			(2.3	)			(7.9	)			(7.2	)

	Total recognized in other comprehensive loss (earnings)			28.2				(43.9	)			3.4

	Total recognized in net periodic pension cost (earnings) and other comprehensive loss (earnings)		$	37.2			$	(40.7	)		$	7.6

	Estimated amortization for the following year:
	Amortization of net loss		$	6			$	2.4			$	7.7




The following weighted average assumptions were used at December 31 in determining the plan’s pension benefit obligation:



		December 31,
		2014				2013
Discount rate			4	%			4.75	%
Weighted average expected long-term rate of return on plan assets			7.5	%			7.5	%

The following weighted average assumptions were used at January 1 in determining the plan’s net periodic pension benefit cost:



		Year Ended December 31,
		2014				2013				2012
Discount rate			4.75	%			4	%			4.5	%
Weighted average expected long-term rate of return on plan assets			7.5	%			7.5	%			7.5	%

The following benefit payments are expected to be paid by the plan (in millions):



2015		$	10.8
2016			11.3
2017			11.8
2018			12.3
2019			12.9
Years 2020 to 2024			73.3

The following is a summary of the plan’s weighted average asset allocations at December 31 by asset category:



		December 31,
Asset Category		2014				2013
Equity securities			65	%			69	%
Debt securities			26	%			24	%
Real estate			9	%			7	%

Total			100	%			100	%


Plan assets are invested in various pooled separate accounts under annuity contracts managed by two life insurance carriers. The plan’s investment policy provides that investments will be allocated in a manner designed to provide a long-term investment return greater than the actuarial assumptions, maximize investment return commensurate with risk and to comply with the Employee Income Retirement Security Act of 1974, as amended (which we refer to as ERISA), by investing the funds in a manner consistent with ERISA’s fiduciary standards. The weighted average expected long-term rate of return on plan assets assumption was determined based on a review of the asset allocation strategy of the plan using expected ten-year return assumptions for all of the asset classes in which the plan was invested at December 31, 2014 and 2013. The ten-year return assumptions used in the valuation were based on data provided by the plan’s external investment advisors.

The following is a summary of the plan’s assets carried at fair value as of December 31 by level within the fair value hierarchy (in millions):



		December 31,
Fair Value Hierarchy		2014				2013
Level 1		$	—			$	—
Level 2			116.1				158.8
Level 3			101.1				96.1

Total fair value		$	217.2			$	254.9


The plan’s Level 2 assets consist of ownership interests in various pooled separate accounts within a life insurance carrier’s group annuity contract. The fair value of the pooled separate accounts is determined based on the net asset value of the respective funds, which is obtained from the carrier and determined each business day with issuances and redemptions of units of the funds made based on the net asset value per unit as determined on the valuation date. We have not adjusted the net asset values provided by the carrier. There are no restrictions as to the plan’s ability to redeem its investment at the net asset value of the respective funds as of the reporting date. The plan’s Level 3 assets consist of pooled separate accounts within another life insurance carrier’s annuity contracts for which fair value has been determined by an independent valuation. Due to the nature of these annuity contracts, our management makes assumptions to determine how a market participant would price these Level 3 assets. In determining fair value, the future cash flows to be generated by the annuity contracts were estimated using the underlying benefit provisions specified in each contract, market participant assumptions and various actuarial and financial models. These cash flows were then discounted to present value using a risk-adjusted rate that takes into consideration market based rates of return and probability-weighted present values.



The following is a reconciliation of the beginning and ending balances for the Level 3 assets of the plan measured at fair value (in millions):



		Year Ended December 31,
		2014				2013
Fair value at January 1		$	96.1			$	91.1
Settlements			—				—
Unrealized gains			5				5

Fair value at December 31		$	101.1			$	96.1


We were not required under the Internal Revenue Code (which we refer to as IRC) to make any minimum contributions to the plan for each of the 2014, 2013 and 2012 plan years. This level of required funding is based on the plan being frozen and the aggregate amount of our historical funding. During 2014, we did not make discretionary contributions to the plan. During 2013 and 2012, we made discretionary contributions of $6.3 million and $7.2 million, respectively, to the plan.

In August 2014, we decided to pursue a pension de-risking strategy to reduce the size of our long-term U.S. defined benefit pension plan obligations and the volatility of these obligations on our balance sheet. On September 12, 2014, the fiduciaries of the plan began offering certain former employees who were participants in the plan, the option of receiving the value of their pension benefit in a lump sum payment or as an accelerated reduced annuity, in lieu of monthly annuity payments when they retire. The voluntary offer was made to approximately 2,500 terminated, vested participants in the plan whose employment terminated with the company prior to August 1, 2014 and who had not commenced benefit payments as of November 1, 2014. 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. The aggregate lump sum payout made in fourth quarter 2014 was $43.3 million. All payouts related to this offer were made using assets from the plan. This lump sum payout project reduced the Plan’s pension benefit obligation by approximately $60.0 million, while improving its pension underfunding by almost $17.0 million as of December 31, 2014. We recorded a non-cash pretax settlement charge of $12.0 million in the fourth quarter of 2014 based on the number of participants accepting the lump sum payment option, the actual return on plan assets and various actuarial assumptions, including discount rate, long-term rate of return on assets, retirement age and mortality at the remeasurement date.

We also have a qualified contributory savings and thrift (401(k)) plan covering the majority of our domestic employees. For eligible employees who have met the plan’s age and service requirements to receive matching contributions, we match 100% of pre-tax and Roth elective deferrals up to a maximum of 5.0% of eligible compensation, subject to Federal limits on plan contributions and not in excess of the maximum amount deductible for Federal income tax purposes. Effective January 1, 2014, employees must be employed and eligible for the plan on the last day of the plan year to receive a matching contribution, subject to certain exceptions enumerated in the plan document. Matching contributions are subject to a five-year graduated vesting schedule. We expensed $38.0 million, $36.8 million and $33.0 million related to the plan in 2014, 2013 and 2012, respectively.

We also have a nonqualified deferred compensation plan, the Supplemental Savings and Thrift Plan, for certain employees who, due to Internal Revenue Service (which we refer to as the IRS) rules, cannot take full advantage of our matching contributions under the 401(k) plan. The plan permits these employees to annually elect to defer a portion of their compensation until their retirement or a future date. Our matching contributions to this plan (up to a maximum of the lesser of a participant’s elective deferral of base salary, annual bonus and commissions or 5.0% of eligible compensation, less matching amounts contributed under the 401(k) plan) are also at the discretion of our board of directors. We contributed $3.7 million, $2.8 million and $2.5 million to a rabbi trust maintained under the plan in 2014, 2013 and 2012, respectively. The fair value of the assets in the plan’s rabbi trust at December 31, 2014 and 2013, including employee contributions and investment earnings, was $177.5 million and $148.2 million, respectively, and has been included in other noncurrent assets and the corresponding liability has been included in other noncurrent liabilities in the accompanying consolidated balance sheet.

We also have several foreign benefit plans, the largest of which is a defined contribution plan that provides for us to make contributions of 5.0% of eligible compensation. In addition, the plan allows for voluntary contributions by U.K. employees, which we match 100%, up to a maximum of an additional 5.0% of eligible compensation. Net expense for foreign retirement plans amounted to $29.7 million, $18.1 million and $16.0 million in 2014, 2013 and 2012, respectively.

In 1992, we amended our health benefits plan to eliminate retiree coverage, except for retirees and those employees who had already attained a specified age and length of service at the time of the amendment. The retiree health plan is contributory, with contributions adjusted annually, and is funded on a pay-as-you-go basis. The postretirement benefit obligation and the unfunded status of the plan as of December 31, 2014 and 2013 were $4.1 million and $3.1 million, respectively. The net periodic postretirement benefit (income) cost of the plan amounted to ($0.5 million), ($0.5 million) and ($0.1 million) in 2014, 2013 and 2012, respectively.

Investments

12 Months Ended

Dec. 31, 2014

Equity Method Investments and Joint Ventures [Abstract]

Investments

The following is a summary of our investments and the related funding commitments (in millions):

December 31, 2014

December 31,

Funding

2013

Assets

Commitments

Assets

Chem-Mod LLC

—

Chem-Mod International LLC

—

C-Quest Technology LLC and C-Quest Technologies International LLC

—

Clean-coal investments:

Controlling interest in five limited liability companies that own fourteen 2009 Era Clean Coal Plants

17.3

—

18.3

Non-controlling interest in one limited liability companies that owns one 2011 Era Clean Coal Plants

—

1.1

Controlling interest in thirteen limited liability companies that own nineteen 2011 Era Clean Coal Plants

54.5

—

59.3

Other investments

3.2

2.9

3.7

Total investments

2.9

90.4

Chem-Mod LLC - At December 31, 2014, we held a 46.54% controlling interest in Chem-Mod. Chem-Mod possesses the exclusive marketing rights, in the U.S. and Canada, for technologies used to reduce emissions created during the combustion of coal. The refined coal production plants discussed below, as well as those owned by other unrelated parties, license and use Chem-Mod’s proprietary technologies, The Chem-Mod™ Solution, in the production of refined coal. The Chem-Mod™ Solution uses a dual injection sorbent system to reduce mercury, sulfur dioxide and other emissions at coal-fired power plants.

We believe that the application of The Chem-Mod™ Solution qualifies for refined coal tax credits under IRC Section 45 when used with refined coal production plants placed in service by December 31, 2011 or 2009. Chem-Mod has been marketing its technologies principally to coal-fired power plants owned by utility companies, including those utilities that are operating with the IRC Section 45 refined coal production plants in which we hold an investment.

Chem-Mod is determined to be a variable interest entity (which we refer to as a VIE). We are the controlling manager of Chem-Mod and therefore consolidate its operations into our consolidated financial statements. At December 31, 2014, total assets and total liabilities of this VIE included in our consolidated balance sheet were $10.2 million and $1.2 million, respectively. For 2014, total revenues and expenses were $69.1 million and $38.4 million (including non-controlling interest of $35.3 million), respectively. We are under no obligation to fund Chem-Mod’s operations in the future.

Chem-Mod International LLC - At December 31, 2014, we held a 31.52% non-controlling ownership interest in Chem-Mod International. Chem-Mod International has the rights to market The Chem-Mod™ Solution in countries other than the U.S. and Canada. Such marketing activity has been limited to date.

C-Quest Technology LLC and C-Quest Technologies International LLC (together, C-Quest) - At December 31, 2014, we held a non-controlling 12% interest in C-Quest’s global entities, which is an increase of 4% resulting from the transaction described below. C-Quest possesses rights, information and technology for the reduction of carbon dioxide emissions created by burning fossil fuels. Thus far, C-Quest’s operations have been limited to laboratory testing. C-Quest is determined to be a VIE, but due to our lack of control over the operation of C-Quest, we do not consolidate this investment into our consolidated financial statements. Prior to August 1, 2013, we had an option to acquire an additional 19% interest in C-Quest’s global entities for $9.5 million at any time on or prior to August 1, 2016. On August 1, 2013, we loaned the majority owner $2.0 million at a 2% interest rate, which was to mature on May 15, 2014. Also on August 1, 2013, the option to acquire the 19% interests was extended to August 15, 2016. The loan was to be repaid in cash or by delivery of an additional 4% ownership interest in C-Quest’s global entities. On March 31, 2014, we accepted payment of the loan by delivery of the additional 4% ownership interest, therefore our remaining option was reduced to 15% and the remaining purchase price was reduced to $7.5 million.

Clean Coal Investments -

•

We have investments in limited liability companies that own 34 refined coal production plants which produce refined coal using proprietary technologies owned by Chem-Mod. We believe the production and sale of refined coal at these plants is qualified to receive refined coal tax credits under IRC Section 45. The fourteen plants placed in service prior to December 31, 2009 (which we refer to as the 2009 Era Plants) are eligible to receive tax credits through 2019 and the twenty plants placed in service prior to December 31, 2011 (which we refer to as the 2011 Era Plants) are eligible to receive tax credits through 2021.

•

On March 1, 2013, we purchased an additional ownership interest in twelve of the 2009 Era Plants from a co-investor. For nine of the plants, our ownership increased from 24.5% to 49.5%. For the other three of the plants, our ownership increased from 25.0% to 60.0%. Our investment in these plants had been accounted for under the equity method of accounting. As of March 1, 2013, we consolidated the operations of the limited liability company that owns these three plants. For 2014, total revenues and expenses recorded in our consolidated statement of earnings related to this acquisition were $260.9 million and $264.3 million, respectively. For 2013, total revenues and expenses recorded in our consolidated statement of earnings related to this acquisition were $128.3 million and $133.5 million, respectively.

•

Our purchase price for the additional ownership interests in these twelve plants was the assumption of the promissory note that we received as consideration for the co-investor’s purchase of ownership interests in three of the 2009 Era Plants on March 1, 2010, which had a carrying value, including accrued interest, of $8.0 million at March 1, 2013, plus the payment of cash and other consideration of $5.0 million. We recognized a gain of $11.4 million as a component of other net revenues in the accompanying consolidated statement of earnings, which included the increase in fair value of our prior 25% equity interest in the limited liability company upon the acquisition of the additional 35% equity interest, and recorded $26.3 million of fixed and other amortizable intangible assets and $6.8 million of other assets in connection with this transaction. The carrying value of our prior non-controlling interest in the limited liability company was $4.8 million as of the acquisition date. The fair value of our prior non-controlling interest in the limited liability company was determined by allocating, on a pro rata basis, the fair value of the limited liability company as adjusted for our lack of control in our prior ownership position. We determined the fair value of the limited liability company using similar valuation techniques to those discussed in Note 3 to these consolidated financial statements.

•

On September 1, 2013, we purchased a 99% interest in a limited liability company that has ownership interests in four limited liability companies that own five 2011 Era Plants. The purchase price was $4.0 million in cash plus a $10.0 million note with 3% interest due in installments through December 19, 2021. Total revenues and expenses recorded in our consolidated statement of earnings, for 2014 related to the acquisition, were $84.0 million and $93.0 million, respectively. Total revenues and expenses recorded in our consolidated statement of earnings, for 2013 related to the acquisition, were $33.7 million and $36.9 million, respectively.

•

On March 1, 2014, we purchased additional ownership interests from a co-investor in four limited liability companies that own seven 2009 Era Plants and five 2011 Era Plants. We recognized a gain of $25.6 million as a component of other net revenues in the accompanying consolidated statement of earnings, which included the increase in fair value of our prior equity interests in the limited liability companies upon the acquisition of the additional equity interests, and recorded $26.3 million of fixed and other amortizable intangible assets in connection with this transaction. The carrying value of our prior non-controlling interest in the limited liability company was $15.6 million as of the acquisition date. The fair value of our prior non-controlling interest in the limited liability company was determined by allocating, on a pro rata basis, the fair value of the limited liability company as adjusted for our lack of control in our prior ownership position. We determined the fair value of the limited liability company using similar valuation techniques to those discussed in Note 3 to these consolidated financial statements. For seven of the 2009 Era Plants, our ownership increased from 49.5% to 100%. For the 2011 Era plants, our ownership increased from 48.8% to 90.0% for one of the plants, from 49.0% to 100.0% for three of the plants and from 98.0% to 100.0% for one of the plants. Our investments in the plants where our ownership was less than 50% had been accounted for under the equity method of accounting. As of March 1, 2014 we consolidate the operations of the limited liability companies that own these plants. Total revenues and expenses recorded in our consolidated statement of earnings, for 2014 related to the acquisition, were $381.6 million and $405.7 million, respectively.

•

As of December 31, 2014:

•

Twenty-six of the plants have long-term production contracts.

•

The remaining eight plants are in various stages of seeking and negotiating long-term production contracts.

•

We have a non-controlling interest in one plant, which is owned by a limited liability company (which we refer to as a LLC). We have determined that this LLC is a VIE, for which we are not the primary beneficiary. At December 31, 2014, total assets and total liabilities of this VIE were $4.4 million and $1.4 million, respectively. For 2014, total revenues and expenses of this VIE were $33.4 million and $41.0 million, respectively.

•

We and our co-investors each fund our portion of the on-going operations of the limited liability companies in proportion to our investment ownership percentages. Other than our portion of the on-going operational funding, there are no additional amounts that we are committed to related to funding these investments.

Other Investments - At December 31, 2014, we owned a non-controlling, minority interest in four venture capital funds totaling $3.2 million, a 20% non-controlling interest in an investment management company totaling $0.5 million, twelve certified low-income housing developments with zero carrying value and two real estate entities with zero carrying value. The low-income housing developments and real estate entities have been determined to be VIEs, but are not required to be consolidated due to our lack of control over their respective operations. At December 31, 2014, total assets and total liabilities of these VIEs were approximately $60.0 million and $20.0 million, respectively.

Commitments_Contingencies_and_

Commitments, Contingencies and Off-Balance Sheet Arrangements	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Off-Balance Sheet Arrangements	14	Commitments, Contingencies and Off-Balance Sheet Arrangements
	In connection with our investing and operating activities, we have entered into certain contractual obligations and commitments. See Notes 7 and 13 to our consolidated financial statements for additional discussion of these obligations and commitments. Our future minimum cash payments, including interest, associated with our contractual obligations pursuant to the note purchase agreements and Credit Agreement, Premium Financing Debt Facility, operating leases and purchase commitments at December 31, 2014 were as follows (in millions):


			Payments Due by Period
	Contractual Obligations		2015			2016			2017			2018			2019		Thereafter		Total
	Note purchase agreements		$	—		$	50		$	300		$	100		$	100	$	1,575.00	$	2,125.00
	Credit Agreement			140			—			—			—			—		—		140
	Premium Financing Debt Facility			127.9			—			—			—			—		—		127.9
	Interest on debt			100.9			100.4			97.5			77.5			73.2		323.9		773.4

	Total debt obligations			368.8			150.4			397.5			177.5			173.2		1,898.90		3,166.30
	Operating lease obligations			99			81.7			68.7			49.8			38.8		131.3		469.3
	Less sublease arrangements			(1.4	)		(0.7	)		(0.3	)		(0.1	)		—		—		(2.5	)
	Outstanding purchase obligations			29.7			5.4			0.9			0.3			—		—		36.3

	Total contractual obligations		$	496.1		$	236.8		$	466.8		$	227.5		$	212	$	2,030.20	$	3,669.40

	The amounts presented in the table above may not necessarily reflect our actual future cash funding requirements, because the actual timing of the future payments made may vary from the stated contractual obligation.
	Note Purchase Agreements, Credit Agreement and Premium Financing Debt Facility - See Note 7 to our consolidated financial statements for a discussion of the terms of the note purchase agreements, the Credit Agreement and Premium Debt Facility.
	Operating Lease Obligations - Our corporate segment’s executive offices and certain subsidiary and branch facilities of our brokerage and risk management segments are located at Two Pierce Place, Itasca, Illinois, where we lease approximately 306,000 square feet of space, or approximately 60% of the building. The lease commitment on this property expires February 28, 2018.
	We generally operate in leased premises at our other locations. Certain of these leases have options permitting renewals for additional periods. In addition to minimum fixed rentals, a number of leases contain annual escalation clauses which are generally related to increases in an inflation index.
	Total rent expense, including rent relating to cancelable leases and leases with initial terms of less than one year, amounted to $122.0 million in 2014, $91.3 million in 2013 and $91.0 million in 2012.
	We have leased certain office space to several non-affiliated tenants under operating sublease arrangements. In the normal course of business, we expect that certain of these leases will not be renewed or replaced. We adjust charges for real estate taxes and common area maintenance annually based on actual expenses, and we recognize the related revenues in the year in which the expenses are incurred. These amounts are not included in the minimum future rentals to be received in the contractual obligations table above.
	Outstanding Purchase Obligations - We typically do not have a material amount of outstanding purchase obligations at any point in time. The amount disclosed in the contractual obligations table above represents the aggregate amount of unrecorded purchase obligations that we had outstanding at December 31, 2014. These obligations represent agreements to purchase goods or services that were executed in the normal course of business.
	Off-Balance Sheet Commitments - Our total unrecorded commitments associated with outstanding letters of credit, financial guarantees and funding commitments at December 31, 2014 were as follows (in millions):


																			Total
			Amount of Commitment Expiration by Period																Amounts
	Off-Balance Sheet Commitments		2015			2016			2017			2018			2019		Thereafter		Committed
	Letters of credit		$	—		$	—		$	—		$	—		$	—	$	22.6	$	22.6
	Financial guarantees			0.8			0.8			0.8			0.8			0.9		16.5		20.6
	Funding commitments			—			—			—			—			—		2.9		2.9

	Total commitments		$	0.8		$	0.8		$	0.8		$	0.8		$	0.9	$	42	$	46.1

	Since commitments may expire unused, the amounts presented in the table above do not necessarily reflect our actual future cash funding requirements. See Note 13 to our consolidated financial statements for a discussion of our funding commitments related to our corporate segment and the Off-Balance Sheet Debt section below for a discussion of other letters of credit. All of the letters of credit represent multiple year commitments that have annual, automatic renewing provisions and are classified by the latest commitment date.

	Since January 1, 2002, we have acquired 339 companies, all of which were accounted for using the acquisition method for recording business combinations. Substantially all of the purchase agreements related to these acquisitions contain provisions for potential earnout obligations. For all of our acquisitions made in the period from 2011 to 2014 that contain potential earnout obligations, such obligations are measured at fair value as of the acquisition date and are included on that basis in the recorded purchase price consideration for the respective acquisition. The amounts recorded as earnout payables are primarily based upon estimated future potential operating results of the acquired entities over a two- to three-year period subsequent to the acquisition date. The aggregate amount of the maximum earnout obligations related to these acquisitions was $549.8 million, of which $205.3 million was recorded in our consolidated balance sheet as of December 31, 2014 based on the estimated fair value of the expected future payments to be made.
	Off-Balance Sheet Debt - Our unconsolidated investment portfolio includes investments in enterprises where our ownership interest is between 1% and 50%, in which management has determined that our level of influence and economic interest is not sufficient to require consolidation. As a result, these investments are accounted for under the equity method. None of these unconsolidated investments had any outstanding debt at December 31, 2014 or 2013 that was recourse to us.
	At December 31, 2014, we had posted two letters of credit totaling $11.3 million in the aggregate, related to our self-insurance deductibles, for which we had a recorded liability of $9.7 million. We have an equity investment in a rent-a-captive facility, which we use as a placement facility for certain of our insurance brokerage operations. At December 31, 2014, we had posted seven letters of credit totaling $6.3 million to allow certain of our captive operations to meet minimum statutory surplus requirements and for additional collateral related to premium and claim funds held in a fiduciary capacity. At December 31, 2014, we had posted one letter of credit totaling $5.0 million to support our potential obligation under a client’s insurance program. These letters of credit have never been drawn upon.
	Our commitments associated with outstanding letters of credit, financial guarantees and funding commitments at December 31, 2014 were as follows (all dollar amounts in table are in millions):


	Description, Purpose and Trigger		Collateral		Compensation	Maximum			Liability
	Description, Purpose and Trigger		Collateral		to Us	Exposure			Recorded
	Venture capital funds
	Funding commitment to two funds - $1.5 million and $1.4 million expire in 2019 and 2023, respectively Trigger - Agreed conditions met		None		None	$	2.9		$	—
	Other
	Credit support under letters of credit for deductibles due by us on our own insurance coverages - expires after 2019 Trigger - We do not reimburse the insurance companies for deductibles the insurance companies advance on behalf of us		None		None		11.3			9.7
	Credit enhancement under letters of credit for our captive insurance operations to meet minimum statutory capital requirements - expires after 2019 Trigger - Dissolution or catastrophic financial results of the operation		None		Reimbursement		6.3			—
			None		of LOC fees		6.3			—
	Credit support under letters of credit for clients’ claim funds held by our Bermuda captive insurance operation in a fiduciary capacity - expires after 2019 Trigger - Investments fall below prescribed levels		None		Reimbursement		5			—
			None		of LOC fees		5			—
	Financial guarantee of a mortgage loan to a U.K.-based employee - expires when mortgage balance is reduced to $6.4 million Trigger - Default on mortgage payments		-1		None		9.1			—
	Financial guarantees of loans to 37 Canadian-based employees - expires when loan balances are reduced to zero from 2017 through 2029 - Principal and interest payments are paid quarterly Trigger - Default on loan payments		-2		None		11.5			—

						$	46.1		$	9.7


	-1	The guarantee has no collateral. The mortgage loan has a lien on real property with an appraised value of approximately $11.0 million.
	-2	The guarantees are collateralized by shares in minority holdings of our Canadian operating companies.

Since commitments may expire unused, the amounts presented in the table above do not necessarily reflect our actual future cash funding requirements.
Litigation, Regulatory and Taxation Matters - We are a defendant in various legal actions incidental to the nature of our business including but not limited to matters related to employment practices, alleged breaches of non-compete or other restrictive covenants, theft of trade secrets, breaches of fiduciary duties and related causes of action. We are also periodically the subject of inquiries and investigations by regulatory and taxing authorities into various matters related to our business. Neither the outcomes of these matters nor their effect upon our business, financial condition or results of operations can be determined at this time.
Our micro-captive advisory services are the subject of an investigation by the Internal Revenue Service (IRS). Additionally, the IRS has initiated audits for the 2012 tax year of over 100 of the micro-captive insurance companies organized and/or managed by us. Among other matters, the IRS is investigating whether we have been acting as a tax shelter promoter in connection with these operations. While the IRS has not made any specific allegations relating to our operations, if the IRS were to successfully assert that the micro-captives organized and/or managed by us do not meet the requirements of IRC Section 831(b), we could be subject to monetary claims by the IRS and/or our micro-captive clients, and our future earnings from our micro-captive operations could be materially adversely affected, any of which could negatively impact the overall captive business and adversely affect our consolidated results of operations and financial condition. Due to the early stage of the investigation and the fact that the IRS has not made any allegation against us at this time, we are not able to reasonably estimate the amount of any potential loss in connection with this investigation.
In July 2014, we were named in a lawsuit which asserts that us, our subsidiary, Gallagher Clean Energy, LLC, and Chem-Mod LLC are liable for infringement of a patent held by Nalco Company. The complaint seeks a judgment of infringement, damages, costs and attorneys’ fees, and injunctive relief. We and the other defendants dispute the allegations contained in the complaint and intend to defend this matter vigorously. On September 30, 2014, we filed a motion to dismiss the complaint on behalf of all defendants. On February 4, 2015, our motion to dismiss was granted by the court; however, the court also granted Nalco Company 30 days to file an amended complaint. We believe that the probability of a material loss is remote. However, litigation is inherently uncertain and it is not possible to predict the ultimate disposition of this proceeding.
Contingent Liabilities - We purchase insurance to provide protection from errors and omissions (which we refer to as E&O) claims that may arise during the ordinary course of business. We currently retain the first $5.0 million of each and every E&O claim. Our E&O insurance provides aggregate coverage for E&O losses up to $175.0 million in excess of our retained amounts. We have historically maintained self-insurance reserves for the portion of our E&O exposure that is not insured. We periodically determine a range of possible reserve levels using actuarial techniques that rely heavily on projecting historical claim data into the future. Our E&O reserve in the December 31, 2014 consolidated balance sheet is above the lower end of the most recently determined actuarial range by $1.4 million and below the upper end of the actuarial range by $6.2 million. We can make no assurances that the historical claim data used to project the current reserve levels will be indicative of future claim activity. Thus, the E&O reserve level and corresponding actuarial range could change in the future as more information becomes known, which could materially impact the amounts reported and disclosed herein.
Tax-advantaged Investments No Longer Held - Between 1996 and 2007, we developed and then sold portions of our ownership in various energy related investments, many of which qualified for tax credits under IRC Section 29. In connection with the sales to other investors, we provided various indemnifications. At December 31, 2014, the maximum potential amount of future payments that we could be required to make under these indemnifications totaled approximately $32.0 million, net of the applicable income tax benefit. In addition, we recorded tax benefits in connection with our ownership in these investments. At December 31, 2014, we had exposure on $117.0 million of previously earned tax credits. In 2004, 2007 and 2009, the IRS examined several of these investments and all examinations were closed without any changes being proposed by the IRS. However, any future adverse tax audits, administrative rulings or judicial decisions could disallow previously claimed tax credits or cause us to be subject to liability under our indemnification obligations. Because of the contingent nature of these exposures, no liabilities have been recorded in our December 31, 2014 consolidated balance sheet related to these indemnification obligations.

Income_Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	15	Income Taxes
	We and our principal domestic subsidiaries are included in a consolidated U.S. Federal income tax return. Our international subsidiaries file various income tax returns in their jurisdictions. The foreign earnings before income taxes are $2.5 million in 2014 as compared to $43.7 million in 2013. Earnings before income taxes include the impact of intercompany interest expense between domestic and foreign legal entities. Foreign intercompany interest expense was $76.5 million in 2014 compared to $16.6 million in 2013. Domestic intercompany interest income was $76.5 million in 2014 compared to $16.6 million in 2013. Significant components of earnings before income taxes and the provision for income taxes are as follows (in millions):


			Year Ended December 31,
			2014				2013			2012
	Earnings before income taxes:
	Domestic		$	264.9			$	230.8		$	234.7
	Foreign, principally Australia, Canada, New Zealand and the U.K.			2.5				43.7			10.6

			$	267.4			$	274.5		$	245.3

	Provision (benefit) for income taxes:
	Federal:
	Current		$	38.8			$	29		$	45.4
	Deferred			(96.6	)			(47.7	)		(14.6	)

				(57.8	)			(18.7	)		30.8

	State and local:
	Current			19.5				10.6			17.3
	Deferred			(1.1	)			(0.6	)		(2.9	)

				18.4				10			14.4

	Foreign:
	Current			30.5				28.5			8.7
	Deferred			(27.1	)			(13.9	)		(3.6	)

				3.4				14.6			5.1

	Total provision (benefit) for income taxes		$	(36.0	)		$	5.9		$	50.3

	A reconciliation of the provision for income taxes with the U.S. Federal statutory income tax rate is as follows (in millions, except percentages):


			Year Ended December 31,
			2014							2013						2012
			Amount				% of			Amount			% of			Amount			% of
							Pretax						Pretax						Pretax
							Earnings						Earnings						Earnings
	Federal statutory rate		$	93.6				35		$	96.1			35		$	85.9			35
	State income taxes - net of Federal benefit			12				4.5			6.5			2.4			9.4			3.8
	Foreign taxes			0.8				0.3			(0.8	)		(0.3	)		0.9			0.4
	Alternative energy, foreign and other tax credits			(145.5	)			(54.4	)		(93.8	)		(34.2	)		(45.3	)		(18.5	)
	Foreign dividends and other permanent differences			(6.1	)			(2.3	)		(2.5	)		(0.9	)		(2.7	)		(1.1	)
	Nondeductible employee compensation			5.4				2			—			—			—			—
	Changes in unrecognized tax benefits			2.4				0.9			1.5			0.5			0.6			0.2
	Change in valuation allowance			—				—			0.5			0.2			0.3			0.1
	Other			1.4				0.5			(1.6	)		(0.6	)		1.2			0.6

	Provision (benefit) for income taxes		$	(36.0	)			(13.5	)	$	5.9			2.1		$	50.3			20.5


	A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows (in millions):


			December 31,
			2014				2013
	Gross unrecognized tax benefits at January 1		$	9.2			$	6.7
	Increases in tax positions for current year			2.6				2.9
	Settlements			—				—
	Lapse in statute of limitations			(1.0	)			(1.4	)
	Increases in tax positions for prior years			1.7				2.3
Decreases in tax positions for prior years			—				(1.3	)

Gross unrecognized tax benefits at December 31		$	12.5			$	9.2

The total amount of net unrecognized tax benefits that, if recognized, would affect the effective tax rate was $8.2 million and $5.9 million at December 31, 2014 and 2013, respectively. We accrue interest and penalties related to unrecognized tax benefits in our provision for income taxes. At December 31, 2014 and 2013, we had accrued interest and penalties related to unrecognized tax benefits of $0.8 million and $0.6 million, respectively.
We file income tax returns in the U.S. and in various state, local and foreign jurisdictions. We are routinely examined by tax authorities in these jurisdictions. At December 31, 2014, we had been examined by the IRS through calendar year 2010. The IRS is currently conducting a routine examination of calendar years 2011 and 2012. A number of foreign, state and local examinations are currently ongoing. It is reasonably possible that our gross unrecognized tax benefits may change within the next twelve months. However, we believe any changes in the recorded balance would not have a significant impact on our consolidated financial statements.
Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets and liabilities are as follows (in millions):


		December 31,
		2014				2013
Deferred tax assets:
Alternative minimum tax and other credit carryforwards		$	233.4			$	147.4
Accrued and unfunded compensation and employee benefits			166.9				136.6
Amortizable intangible assets			66.7				12.5
Compensation expense related to stock options			14.7				14.2
Accrued liabilities			31				30.2
Accrued pension liability			24.3				9.2
Investments			10				9
Net operating loss carryforwards			10				11.9
Deferred rent liability			8.5				8.2
Other			4.8				6.8

Total deferred tax assets			570.3				386
Valuation allowance for deferred tax assets			(75.5	)			(21.3	)

Deferred tax assets			494.8				364.7

Deferred tax liabilities:
Nondeductible amortizable intangible assets			338.7				184
Investment-related partnerships			26.6				13.2
Depreciable fixed assets			8.8				5.2
Other prepaid items			4.3				4.7
Accrued liabilities			—				2.4

Total deferred tax liabilities			378.4				209.5

Net deferred tax assets		$	116.4			$	155.2

At December 31, 2014 and 2013, $102.2 million and $84.9 million, respectively, of deferred tax assets have been included in other current assets in the accompanying consolidated balance sheet. At December 31, 2014 and 2013, $4.3 million and $5.0 million, respectively, of deferred tax liabilities have been included in other current liabilities and $374.1 million and $204.5 million, respectively, have been included in noncurrent liabilities in the accompanying consolidated balance sheet. Alternative minimum tax credits of $108.2 million have an indefinite life, general business tax credits of $124.3 million expire, if not utilized, in 2033 and other tax credits of $0.9 million begin to expire, if not utilized, in 2018. We expect the historically favorable trend in earnings before income taxes to continue in the foreseeable future. Accordingly, we expect to make full use of the net deferred tax assets. Valuation allowances have been established for certain foreign intangible assets and various state net operating loss carryforwards that may not be utilized in the future.
We do not provide for U.S. Federal income taxes on the undistributed earnings ($279.9 million and $224.2 million at December 31, 2014 and 2013, respectively) of foreign subsidiaries which are considered permanently invested outside of the U.S. The amount of unrecognized deferred tax liability on these undistributed earnings was $36.2 million and $35.2 million at December 31, 2014 and 2013, respectively.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Earnings	12 Months Ended
Accumulated Other Comprehensive Earnings	Dec. 31, 2014
Equity [Abstract]
Accumulated Other Comprehensive Earnings	16	Accumulated Other Comprehensive Earnings
	The after-tax components of our accumulated comprehensive earnings (loss) consist of the following:


			Pension			Foreign			Fair Value			Accumulated
			Liability			Currency			of Derivative			Comprehensive
						Translation			Instruments			Earnings (Loss)
	Balance as of January 1, 2012		$	(49.0	)	$	4.4		$	(2.6	)	$	(47.2	)
	Net change in period			(3.4	)		16.1			1.7			14.4

	Balance as of December 31, 2012			(52.4	)		20.5			(0.9	)		(32.8	)
	Net change in period			26.8			1.6			1.8			30.2

	Balance as of December 31, 2013			(25.6	)		22.1			0.9			(2.6	)
	Net change in period			(18.6	)		(238.4	)		(1.0	)		(258.0	)

	Balance as of December 31, 2014		$	(44.2	)	$	(216.3	)	$	(0.1	)	$	(260.6	)

	The foreign currency translation in 2014, 2013 and 2012 primarily relates to the net impact of changes in the value of the local currencies relative to the U.S. dollar for our operations in Australia, Canada, the Caribbean, India, New Zealand and the U.K. During 2014, 2013 and 2012, $14.3 million, $7.9 million and $7.2 million, respectively, of expense related to the pension liability was reclassified from accumulated other comprehensive loss to compensation expense in the statement of earnings. During 2014, 2013 and 2012, $0.6 million, $0.9 million and $0.2 million, respectively, of expense related to the fair value of derivative investments was reclassified from accumulated other comprehensive loss to the statement of earnings. During 2014, 2013 and 2012, no amounts related to foreign currency translation were reclassified from accumulated other comprehensive loss to the statement of earnings.

Quarterly_Operating_Results_un

Quarterly Operating Results (unaudited)	12 Months Ended
Quarterly Operating Results (unaudited)	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Operating Results (unaudited)	17	Quarterly Operating Results (unaudited)
	Quarterly operating results for 2014 and 2013 were as follows (in millions, except per share data):


			1st		2nd		3rd		4th
	2014
	Total revenues		$	915	$	1,179.30	$	1,286.80	$	1,245.40
	Total expenses			868.7		1,072.20		1,199.10		1,219.10

	Earnings before income taxes		$	46.3	$	107.1	$	87.7	$	26.3

	Net earnings		$	49.3	$	109	$	93.6	$	51.5

	Basic net earnings per share:		$	0.37	$	0.71	$	0.58	$	0.32

	Diluted net earnings per share:		$	0.36	$	0.7	$	0.58	$	0.31

Segment_Information

Segment Information	12 Months Ended
Segment Information	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	18. Segment Information
	We have three reportable operating segments: brokerage, risk management and corporate. The brokerage segment is primarily comprised of our retail and wholesale insurance brokerage operations. The brokerage segment generates revenues through commissions paid by insurance underwriters and through fees charged to our clients. Our brokers, agents and administrators act as intermediaries between insurers and their customers and we do not assume underwriting risks. The risk management segment provides contract claim settlement and administration services for enterprises that choose to self-insure some or all of their property/casualty coverages and for insurance companies that choose to outsource some or all of their property/casualty claims departments. These operations also provide claims management, loss control consulting and insurance property appraisal services. Revenues are principally generated on a negotiated per-claim or per-service fee basis. The corporate segment manages our clean energy and other investments. This segment also holds all of our corporate debt. Allocations of investment income and certain expenses are based on reasonable assumptions and estimates primarily using revenue, headcount and other information. We allocate the provision for income taxes to the brokerage and risk management segments using the local county statutory rates. Reported operating results by segment would change if different methods were applied. Financial information relating to our segments for 2014, 2013 and 2012 is as follows (in millions):


	Year Ended December 31, 2014		Brokerage			Risk			Corporate				Total
	Year Ended December 31, 2014		Brokerage			Management			Corporate				Total
	Revenues:
	Commissions		$	2,083.00		$	—		$	—			$	2,083.00
	Fees			595			663.3			—				1,258.30
	Supplemental commissions			104			—			—				104
	Contingent commissions			84.7			—			—				84.7
	Investment income			40.3			1			—				41.3
	Gains on books of business sales and other			7.3			—			—				7.3
	Revenue from clean coal activities			—			—			1,029.50				1,029.50
	Other - net gain			—			—			18.4				18.4

	Total revenues			2,914.30			664.3			1,047.90				4,626.50

	Compensation			1,715.70			401.6			50.3				2,167.60
	Operating			534.1			173.3			59.8				767.2
	Cost of revenues from clean coal activities			—			—			1,058.90				1,058.90
	Interest			—			—			89				89
	Depreciation			44.7			20.9			3.8				69.4
	Amortization			186.7			2.8			—				189.5
	Change in estimated acquisition earnout payables			17.5			—			—				17.5

	Total expenses			2,498.70			598.6			1,261.80				4,359.10

	Earnings (loss) before income taxes			415.6			65.7			(213.9	)			267.4
	Provision (benefit) for income taxes			151.8			24.5			(212.3	)			(36.0	)

	Net earnings		$	263.8		$	41.2		$	(1.6	)		$	303.4

	Net foreign exchange gain (loss)		$	1.1		$	—		$	(0.6	)		$	0.5
	Revenues:
	United States		$	1,891.30		$	514.7		$	1,048.90			$	3,454.90
	United Kingdom			697.1			29.3			—				726.4
	Australia			128.9			114.2			—				243.1
	Canada			81.8			3.2			—				85
	Other foreign, principally New Zealand			115.2			2.9			(1.0	)			117.1

	Total revenues		$	2,914.30		$	664.3		$	1,047.90			$	4,626.50

	At December 31, 2014
	Identifiable assets:
	United States		$	3,584.30		$	430.3		$	1,032.00			$	5,046.60
	United Kingdom			2,376.40			74			—				2,450.40
	Australia			639.2			2.8			—				642
	Canada			992.2			39			—				1,031.20
	Other foreign, principally New Zealand			821.3			1.6			16.9				839.8

	Total identifiable assets		$	8,413.40		$	547.7		$	1,048.90			$	10,010.00

	Goodwill - net		$	3,427.50		$	22.1		$	—			$	3,449.60
	Amortizable intangible assets - net			1,761.20			14.8			—				1,776.00


	Year Ended December 31, 2013		Brokerage			Risk			Corporate				Total
	Year Ended December 31, 2013		Brokerage			Management			Corporate				Total
	Revenues:
	Commissions		$	1,553.10		$	—		$	—			$	1,553.10
	Fees			450.5			609			—				1,059.50
	Supplemental commissions			77.3			—			—				77.3
	Contingent commissions			52.1			—			—				52.1
Investment income			6.1			2			—				8.1
Gains on books of business sales and other			5.2			—			—				5.2
Revenue from clean coal activities			—			—			412.5				412.5
Other - net gain			—			—			11.8				11.8

Total revenues			2,144.30			611			424.3				3,179.60

Compensation			1,290.40			370.5			24.1				1,685.00
Operating			369.9			146			36.5				552.4
Cost of revenues from clean coal activities			—			—			437.3				437.3
Interest			—			—			50.1				50.1
Depreciation			31.1			19.4			2.9				53.4
Amortization			122.7			2.5			—				125.2
Change in estimated acquisition earnout payables			2.6			(0.9	)		—				1.7

Total expenses			1,816.70			537.5			550.9				2,905.10

Earnings (loss) before income taxes			327.6			73.5			(126.6	)			274.5
Provision (benefit) for income taxes			122.8			27.3			(144.2	)			5.9

Net earnings		$	204.8		$	46.2		$	17.6			$	268.6

Net foreign exchange gain (loss)		$	0.6		$	—		$	(0.4	)		$	0.2
Revenues:
United States		$	1,644.80		$	473.5		$	424.3			$	2,542.60
United Kingdom			400.5			27.4			—				427.9
Australia			47.1			105.5			—				152.6
Canada			29.5			3.1			—				32.6
Other foreign, principally Bermuda			22.4			1.5			—				23.9

Total revenues		$	2,144.30		$	611		$	424.3			$	3,179.60

At December 31, 2013
Identifiable assets:
United States		$	3,219.60		$	419		$	783.8			$	4,422.40
United Kingdom			1,819.50			58.8			—				1,878.30
Australia			214.3			63.6			—				277.9
Canada			107.3			1.5			—				108.8
Other foreign, principally Bermuda			162			1.8			9.3				173.1

Total identifiable assets		$	5,522.70		$	544.7		$	793.1			$	6,860.50

Goodwill - net		$	2,122.90		$	22.3		$	—			$	2,145.20
Amortizable intangible assets - net			1,061.60			17.2			—				1,078.80


Year Ended December 31, 2012		Brokerage			Risk			Corporate				Total
Year Ended December 31, 2012		Brokerage			Management			Corporate				Total
Revenues:
Commissions		$	1,302.50		$	—		$	—			$	1,302.50
Fees			403.2			568.5			—				971.7
Supplemental commissions			67.9			—			—				67.9
Contingent commissions			42.9			—			—				42.9
Investment income			7.2			3.2			—				10.4
Gains on books of business sales and other			3.9			—			—				3.9
Revenue from clean coal activities			—			—			119.6				119.6
Other - net gain			—			—			1.4				1.4

Total revenues			1,827.60			571.7			121				2,520.30

Compensation			1,131.60			347			14.8				1,493.40
Operating			312.7			137.7			32.8				483.2
Cost of revenues from clean coal activities			—			—			111.6				111.6
Interest			—			—			43				43
Depreciation			24.7			16			0.7				41.4
Amortization			96.2			2.8			—				99
Change in estimated acquisition earnout payables			3.6			(0.2	)		—				3.4

Total expenses			1,568.80			503.3			202.9				2,275.00

Earnings (loss) before income taxes			258.8			68.4			(81.9	)			245.3
Provision (benefit) for income taxes			103			25.9			(78.6	)			50.3

Net earnings (loss)		$	155.8		$	42.5		$	(3.3	)		$	195

Net foreign exchange loss		$	(1.6	)	$	(0.1	)	$	(0.2	)		$	(1.9	)
Revenues:
United States		$	1,431.60		$	453.5		$	121			$	2,006.10
United Kingdom			317.8			28.2			—				346
Australia			35.1			86.3			—				121.4
Canada			28.9			3.2			—				32.1
Other foreign, principally Bermuda			14.2			0.5			—				14.7

Total revenues		$	1,827.60		$	571.7		$	121			$	2,520.30

At December 31, 2012
Identifiable assets:
United States		$	2,637.10		$	390.9		$	647.9			$	3,675.90
United Kingdom			1,117.60			52.4			—				1,170.00
Australia			208.4			52.1			—				260.5
Canada			100.7			1.7			—				102.4
Other foreign, principally Bermuda			133			1.5			9				143.5

Total identifiable assets		$	4,196.80		$	498.6		$	656.9			$	5,352.30

Goodwill - net		$	1,451.40		$	21.3		$	—			$	1,472.70
Amortizable intangible assets - net			791.6			18			—				809.6

Schedule_II_Valuation_and_Qual

Schedule II. Valuation and Qualifying Accounts	12 Months Ended
Schedule II. Valuation and Qualifying Accounts	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II. Valuation and Qualifying Accounts	Schedule II
	Arthur J. Gallagher & Co.
	Valuation and Qualifying Accounts


		Balance		Amounts			Adjustments			Balance
		at		Recorded						at End
		Beginning		in						of Year
		of Year		Earnings
		(In millions)
	Year ended December 31, 2014
	Allowance for doubtful accounts	$	6.7	$	2.7		$	1.3	(1)	$	10.7
	Allowance for estimated policy cancellations		4.2		(0.2	)		2.8	(2)		6.8
	Accumulated amortization of expiration lists, noncompete agreements and trade names		544.1		189.5			25.2	(3)		758.8

	Year ended December 31, 2013
	Allowance for doubtful accounts	$	6.6	$	2.7		$	(2.6	)(1)	$	6.7
	Allowance for estimated policy cancellations		4		(0.2	)		0.4	(2)		4.2
	Accumulated amortization of expirationlists, noncompete agreements and trade names		419.3		125.2			(0.4	)(3)		544.1

	Year ended December 31, 2012
	Allowance for doubtful accounts	$	4.8	$	1		$	0.8	(1)	$	6.6
	Allowance for estimated policy cancellations		5.2		(1.6	)		0.4	(2)		4
	Accumulated amortization of expirationlists, noncompete agreements and trade names		321.3		99			(1.0	)(3)		419.3

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations - 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 30 countries and offer client-service capabilities in more than 140 countries globally through a network of correspondent insurance brokers and consultants.
Basis of Presentation	Basis of Presentation - 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.
	Certain reclassifications have been made to the amounts reported in prior years’ consolidated financial statements in order to conform to the current year presentation.
	In the preparation of our consolidated financial statements as of December 31, 2014, 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.
Use of Estimates	Use of Estimates - 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.
Revenue Recognition	Revenue Recognition - Our revenues are derived from commissions, fees and investment income.
	We recognize commission revenues at the later of the billing or the effective date of the related insurance policies, net of an allowance for estimated policy cancellations. We recognize commission revenues related to installment premiums as the installments are billed. We recognize supplemental commission revenues using internal data and information received from insurance carriers that allows us to reasonably estimate the supplemental commissions earned in the period. A supplemental commission is a commission paid by an insurance carrier that is above the base commission paid, is determined by the insurance carrier, and is established annually in advance of the contractual period based on historical performance criteria. We recognize contingent commissions and commissions on premiums directly billed by insurance carriers as revenue when we have obtained the data necessary to reasonably determine such amounts. Typically, we cannot reasonably determine these types of commission revenues until we have received the cash or the related policy detail or other carrier specific information from the insurance carrier. A contingent commission is a commission paid by an insurance carrier based on the overall profit and/or volume of the business placed with that insurance carrier during a particular calendar year and is determined after the contractual period. Commissions on premiums billed directly by insurance carriers to the insureds generally relate to a large number of property/casualty insurance policy transactions, each with small premiums, and comprise a substantial portion of the revenues generated by our employee benefit brokerage operations. Under these direct bill arrangements, the insurance carrier controls the entire billing and policy issuance process. We record the income effects of subsequent premium adjustments when the adjustments become known.
	Fee revenues generated from the brokerage segment primarily relate to fees negotiated in lieu of commissions that we recognize in the same manner as commission revenues. Fee revenues generated from the risk management segment relate to third party claims administration, loss control and other risk management consulting services, which we provide over a period of time, typically one year. We recognize these fee revenues ratably as the services are rendered, and record the income effects of subsequent fee adjustments when the adjustments become known.

	We deduct brokerage expense from gross revenues in our determination of our total revenues. Brokerage expense represents commissions paid to sub-brokers related to the placement of certain business by our brokerage segment. We recognize this expense in the same manner as commission revenues.
	Premiums and fees receivable in the accompanying consolidated balance sheet are net of allowances for estimated policy cancellations and doubtful accounts. The allowance for estimated policy cancellations was $6.8 million and $4.2 million at December 31, 2014 and 2013, respectively, which represents a reserve for future reversals in commission and fee revenues related to the potential cancellation of client insurance policies that were in force as of each year end. The allowance for doubtful accounts was $10.7 million and $6.7 million at December 31, 2014 and 2013, respectively. We establish the allowance for estimated policy cancellations through a charge to revenues and the allowance for doubtful accounts through a charge to operating expenses. Both of these allowances are based on estimates and assumptions using historical data to project future experience. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein. We periodically review the adequacy of these allowances and make adjustments as necessary.
	Investment income primarily includes interest and dividend income (including interest income from our premium financing operations), which is accrued as it is earned. Gains on books of business sales represent one-time gains related to sales of brokerage related businesses, which are primarily recognized on a cash received basis. Revenues from clean coal activities include revenues from consolidated clean coal production plants, royalty income from clean coal licenses and income (loss) related to unconsolidated clean coal production plants, all of which are recognized as earned. Revenues from consolidated clean coal production plants represent sales of refined coal. Royalty income from clean coal licenses represents fee income related to the use of clean coal technologies. Income (loss) from unconsolidated clean coal production plants includes income (losses) related to our equity portion of the pretax results of the clean coal production plants and production based installment sale income from majority investors.
	In May 2014, the Financial Accounting Standards Board (which we refer to as the FASB) issued new accounting guidance on revenue from contracts with customers, which will supersede nearly all existing revenue recognition guidance under U.S. GAAP. The core principal of the new guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. This new guidance is effective for the first quarter of 2017 and early adoption is not permitted. The guidance permits two methods of transition upon adoption; full retrospective and modified retrospective. Under the full retrospective method, prior periods would be restated under the new revenue standard, providing a comparable view across all periods presented. Under the modified retrospective method, prior periods would not be restated. Rather, revenues and other disclosures for pre-2017 periods would be provided in the notes to the financial statements as previously reported under the current revenue standard. Management is currently reviewing the guidance, and the impact from its adoption on our consolidated financial statements cannot be determined at this time.
Claims Handling Obligations	Claims Handling Obligations - We are obligated under certain circumstances to provide future claims handling and certain administrative services for our former global risks brokerage clients in the U.K. Our obligation is the result of following the industry practice of insurance brokers providing future claims handling and administrative services to former clients. In addition, under certain circumstances, our risk management segment operations are contractually obligated to provide contract claim settlement and administration services to our former clients. Accordingly, we record a liability for these deferred run-off obligations based on the estimated costs to provide these future services to former clients. This liability is based on estimates and assumptions using historical data to project future experience. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein. We periodically review (at least annually) the adequacy of this liability and will make adjustments as necessary.
Earnings per Share	Earnings per Share - Basic net earnings per share is computed by dividing net earnings by the weighted average number of common shares outstanding during the reporting period. Diluted net earnings per share is computed by dividing net earnings by the weighted average number of common and common equivalent shares outstanding during the reporting period. Common equivalent shares include incremental shares from dilutive stock options, which are calculated from the date of grant under the treasury stock method using the average market price for the period.
Cash and Cash Equivalents	Cash and Cash Equivalents - Short-term investments, consisting principally of cash and money market accounts that have average maturities of 90 days or less, are considered cash equivalents.
Restricted Cash	Restricted Cash - In our capacity as an insurance broker, we collect premiums from insureds and, after deducting our commissions and/or fees, remit these premiums to insurance carriers. We hold unremitted insurance premiums in a fiduciary capacity until we disburse them, and the use of such funds is restricted by laws in certain states and foreign jurisdictions in which our subsidiaries operate. Various state and foreign agencies regulate insurance brokers and provide specific requirements that limit the type of investments that may be made with such funds. Accordingly, we invest these funds in cash and U.S. Treasury fund accounts. We can earn interest income on these unremitted funds, which is included in investment income in the accompanying consolidated statement of earnings. These unremitted amounts are reported as restricted cash in the accompanying consolidated balance sheet, with the related liability reported as premiums payable to insurance and reinsurance companies. Additionally, several of our foreign subsidiaries are required by various foreign agencies to meet certain liquidity and solvency requirements. We were in compliance with these requirements at December 31, 2014.
	Related to our third party administration business, we are responsible for client claim funds that we hold in a fiduciary capacity. We do not earn any interest income on the funds held. These client funds have been included in restricted cash, along with a corresponding liability in premiums payable to insurance and reinsurance companies in the accompanying consolidated balance sheet.
Derivative Instruments	Derivative Instruments - In the normal course of business, we are exposed to the impact of foreign currency fluctuations that impact our results of operations and cash flows. We utilize a foreign currency risk management program involving foreign currency derivatives that consist of several monthly put/call options designed to hedge a significant portion of our future foreign currency disbursements through various future payment dates. To mitigate the counterparty credit risk we only enter into contracts with carefully selected major financial institutions based upon their credit ratings and other factors. These derivative instrument contracts are cash flow hedges that qualify for hedge accounting and primarily hedge against fluctuations between changes in the British Pound Sterling and Indian Rupee versus the U.S. Dollar. Changes in fair value of the derivative instruments are reflected in other comprehensive earnings in the accompanying consolidated balance sheet. The impact of the hedge at maturity is recognized in the income statement as a component of compensation and operating expenses. These derivative instrument contracts are periodically monitored for hedge ineffectiveness, the amount of which has not been material to the accompanying consolidated financial statements. We do not use derivatives for trading or speculative purposes. In 2014, other net revenues also includes a gain of $1.9 million related to a AU$400.0 million foreign currency derivative investment contract that we executed on April 16, 2014 in connection with the signing of the agreement to acquire the Crombie/OAMPS operations, headquartered in Australia. This contract was designed to hedge a portion of the AU$ denominated purchase price consideration of this acquisition. The derivative investment contract was exercised on June 16, 2014, the date that the Crombie/OAMPS transaction closed. In 2013, other net revenues also includes a gain of $2.6 million related to three foreign currency derivative investment contracts that we executed in September 2013 in connection with the signing of an agreement to acquire The Giles Group of Companies, headquartered in London, England. These contracts were designed to hedge a portion of the GBP denominated purchase price consideration of this acquisition. The derivative investment contracts were exercised on October 31, 2013 and the Giles transaction closed in early November 2013.
Premium Financing	Premium Financing - Seven subsidiaries of the brokerage segment make short-term loans (generally with terms of twelve months or less) to our clients to finance premiums. These 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. We recognize interest income as it is earned over the life of the contract using the “level-yield” method. Unearned interest related to contracts receivable is included in the receivable balance in the accompanying consolidated balance sheet. The outstanding loan receivable balance was $232.6 million and $2.3 million at December 31, 2014 and 2013, respectively.
Fixed Assets	Fixed Assets - We carry fixed assets at cost, less accumulated depreciation, in the accompanying consolidated balance sheet. We periodically review long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying value of the assets may not be recoverable. Under those circumstances, if the fair value were less than the carrying amount of the asset, we would recognize a loss for the difference. Depreciation for fixed assets is computed using the straight-line method over the following estimated useful lives:


			Useful Life
	Computer equipment		Three to five years
	Furniture and fixtures		Three to ten years
	Office equipment		Three to ten years
	Software		Three to five years
	Refined fuel plants		Ten years
	Leasehold improvements		Shorter of the lease term or useful life of the asset
Intangible Assets	Intangible Assets - Intangible assets represent the excess of cost over the estimated fair value of net tangible assets of acquired businesses. Our primary intangible assets are classified as either goodwill, expiration lists, non-compete agreements or trade names. Expiration lists, non-compete agreements and trade names are amortized using the straight-line method over their estimated useful lives (three to fifteen years for expiration lists, three to five years for non-compete agreements and five to fifteen years for trade names), while goodwill is not subject to amortization. The establishment of goodwill, expiration lists, non-compete agreements and trade names and the determination of estimated useful lives are primarily based on valuations we receive from qualified independent appraisers. The calculations of these amounts are based on estimates and assumptions using historical and projected financial information and recognized valuation methods. Different estimates or assumptions could produce different results. We carry intangible assets at cost, less accumulated amortization, in the accompanying consolidated balance sheet.
	We review all of our intangible assets for impairment periodically (at least annually for goodwill) and whenever events or changes in business circumstances indicate that the carrying value of the assets may not be recoverable. We perform such impairment reviews at the division (i.e., reporting unit) level with respect to goodwill and at the business unit level for amortizable intangible assets. In reviewing intangible assets, if the fair value were less than the carrying amount of the respective (or underlying) asset, an indicator of impairment would exist and further analysis would be required to determine whether or not a loss would need to be charged against current period earnings as a component of amortization expense. Based on the results of impairment reviews in 2014, 2013 and 2012, we wrote off $1.8 million, $2.2 million and $3.5 million, respectively, of amortizable intangible assets primarily related to prior year acquisitions of our brokerage segment, which is included in amortization expense in the accompanying consolidated statement of earnings. The determinations of impairment indicators and fair value are based on estimates and assumptions related to the amount and timing of future cash flows and future interest rates. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein.
Income Taxes	Income Taxes - Our tax rate reflects the statutory tax rates applicable to our taxable earnings and tax planning in the various jurisdictions in which we operate. Significant judgment is required in determining the annual effective tax rate and in evaluating uncertain tax positions. We report a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in our tax return. We evaluate our tax positions using a two-step process. The first step involves recognition. We determine whether it is more likely than not that a tax position will be sustained upon tax examination based solely on the technical merits of the position. The technical merits of a tax position are derived from both statutory and judicial authority (legislation and statutes, legislative intent, regulations, rulings and case law) and their applicability to the facts and circumstances of the position. If a tax position does not meet the “more likely than not” recognition threshold, we do not recognize the benefit of that position in the financial statements. The second step is measurement. A tax position that meets the “more likely than not” recognition threshold is measured to determine the amount of benefit to recognize in the financial statements. The tax position is measured as the largest amount of benefit that has a likelihood of greater than 50% of being realized upon ultimate resolution with a taxing authority.
	Uncertain tax positions are measured based upon the facts and circumstances that exist at each reporting period and involve significant management judgment. Subsequent changes in judgment based upon new information may lead to changes in recognition, derecognition and measurement. Adjustments may result, for example, upon resolution of an issue with the taxing authorities, or expiration of a statute of limitations barring an assessment for an issue. We recognize interest and penalties, if any, related to unrecognized tax benefits in our provision for income taxes.
	Tax law requires certain items to be included in our tax returns at different times than such items are reflected in the financial statements. As a result, the annual tax expense reflected in our consolidated statements of earnings is different than that reported in our tax returns. Some of these differences are permanent, such as expenses that are not deductible in our tax returns, and some differences are temporary and reverse over time, such as depreciation expense and amortization expense deductible for income tax purposes. Temporary differences create deferred tax assets and liabilities. Deferred tax liabilities generally represent tax expense recognized in the financial statements for which a tax payment has been deferred, or expense which has been deducted in the tax return but has not yet been recognized in the financial statements. Deferred tax assets generally represent items that can be used as a tax deduction or credit in tax returns in future years for which a benefit has already been recorded in the financial statements.
	We establish or adjust valuation allowances for deferred tax assets when we estimate that it is more likely than not that future taxable income will be insufficient to fully use a deduction or credit in a specific jurisdiction. In assessing the need for the recognition of a valuation allowance for deferred tax assets, we consider whether it is more likely than not that some portion, or all, of the deferred tax assets will not be realized and adjust the valuation allowance accordingly. We evaluate all significant available positive and negative evidence as part of our analysis. Negative evidence includes the existence of losses in recent years. Positive evidence includes the forecast of future taxable income by jurisdiction, tax-planning strategies that would result in the realization of deferred tax assets and the presence of taxable income in prior carryback years. The underlying assumptions we use in forecasting future taxable income require significant judgment and take into account our recent performance. Such estimates and assumptions could change in the future as more information becomes known which could impact the amounts reported and disclosed herein. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the periods in which temporary differences are deductible or creditable.
Fair Value of Financial Instruments	Fair Value of Financial Instruments - Fair value accounting establishes a framework for measuring fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (i.e., an exit price). This framework includes a fair value hierarchy that prioritizes the inputs to the valuation technique used to measure fair value.
	The classification of a financial instrument within the valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels of the hierarchy in order of priority of inputs to the valuation technique are defined as follows:

		•		Level 1 - Valuations are based on unadjusted quoted prices in active markets for identical financial instruments;

		•		Level 2 - Valuations are based on quoted market prices, other than quoted prices included in Level 1, in markets that are not active or on inputs that are observable either directly or indirectly for the full term of the financial instrument; and

		•		Level 3 - Valuations are based on pricing or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement of the financial instrument. Such inputs may reflect management’s own assumptions about the assumptions a market participant would use in pricing the financial instrument.
	The level in the fair value hierarchy within which the fair value measurement is classified is determined based on the lowest level input that is significant to the fair value measure in its entirety.
	The carrying amounts of financial assets and liabilities reported in the accompanying consolidated balance sheet for cash and cash equivalents, restricted cash, premiums and fees receivable, premiums payable to insurance carriers, accrued salaries and bonuses, accounts payable and other accrued liabilities, unearned fees and income taxes payable, at December 31, 2014 and 2013, approximate fair value because of the short-term duration of these instruments. See Note 3 to our consolidated financial statements for the fair values related to the establishment of intangible assets and the establishment and adjustment of earnout payables. See Note 7 to our consolidated financial statements for the fair values related to borrowings outstanding at December 31, 2014 and 2013 under our debt agreements. See Note 12 to our consolidated financial statements for the fair values related to investments at December 31, 2014 and 2013 under our defined benefit pension plan.
Litigation	Litigation - We are the defendant in various legal actions related to claims, lawsuits and proceedings incident to the nature of our business. We record liabilities for loss contingencies, including legal costs (such as fees and expenses of external lawyers and other service providers) to be incurred, when it is probable that a liability has been incurred on or before the balance sheet date and the amount of the liability can be reasonably estimated. We do not discount such contingent liabilities. To the extent recovery of such losses and legal costs is probable under our insurance programs, we record estimated recoveries concurrently with the losses recognized. Significant management judgment is required to estimate the amounts of such contingent liabilities and the related insurance recoveries. In order to assess our potential liability, we analyze our litigation exposure based on available information, including consultation with outside counsel handling the defense of these matters. As these liabilities are uncertain by their nature, the recorded amounts may change due to a variety of different factors, including new developments in, or changes in approach, such as changing the settlement strategy as applicable to each matter.
Stock-Based Compensation	Stock-Based Compensation - We have several employee equity-settled and cash-settled share-based compensation plans. Equity-settled share-based payments to employees include grants of stock options and restricted stock units and are measured based on estimated grant date fair value. We have elected to use the Black-Scholes option pricing model to determine the fair value of stock options on the dates of grant. Restricted stock units are measured based on the fair market values of the underlying stock on the dates of grant. Shares are issued on the vesting dates net of the minimum statutory tax withholding requirements, as applicable, to be paid by us on behalf of our employees. As a result, the actual number of shares issued will be fewer than the actual number of restricted stock units outstanding. Furthermore, we record the liability for withholding amounts to be paid by us as a reduction to additional paid-in capital when paid.
	Cash-settled share-based payments to employees include grants of performance units and stock appreciation rights. The fair value of the amount payable to employees in respect of cash-settled share-based payments is recognized as compensation expense, with a corresponding increase in liabilities, over the vesting period. The liability is remeasured at each reporting date and at settlement date. Any changes in fair value of the liability are recognized as compensation expense.
	We recognize share-based compensation expense over the requisite service period for awards expected to ultimately vest. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs from original estimates.
Employee Stock Purchase Plan	Employee Stock Purchase Plan - We have an employee stock purchase plan (which we refer to as the ESPP), under which the sale of 4.0 million shares of our common stock has been authorized. Eligible employees may contribute up to 15% of their compensation towards the quarterly purchase of our common stock at a purchase price equal to 95% of the lesser of the fair market value of our common stock on the first business day or the last business day of the quarterly offering period. Eligible employees may annually purchase shares of our common stock with an aggregate fair market value of up to $25,000 (measured as of the first day of each quarterly offering period of each calendar year), provided that no employee may purchase more than 2,000 shares of our common stock under the ESPP during any calendar year. At December 31, 2014, 0.3 million shares of our common stock are reserved for future issuance under the ESPP.
Defined Benefit Pension and Other Postretirement Plans	Defined Benefit Pension and Other Postretirement Plans - We recognize in our consolidated balance sheet, an asset for our defined benefit postretirement plans’ overfunded status or a liability for our plans’ underfunded status. We recognize changes in the funded status of our defined benefit postretirement plans in comprehensive earnings in the year in which the changes occur. We use December 31 as the measurement date for our plans’ assets and benefit obligations. See Note 12 to our consolidated financial statements for additional information required to be disclosed related to our defined benefit postretirement plans.
Presentation of Unrecognized Tax Benefits	Presentation of Unrecognized Tax Benefits
	In July 2013, the FASB issued ASU 2013 11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists,” which provides explicit guidance on the presentation of certain unrecognized tax benefits in the financial statements that did not previously exist. The guidance provides that a liability related to an unrecognized tax benefit would be offset against a deferred tax asset for a net operating loss carryforward, a similar tax loss or a tax credit carryforward if such settlement is required or expected in the event the uncertain tax position is disallowed. In that case, the liability associated with the unrecognized tax benefit is presented in the financial statements as a reduction to the related deferred tax asset. In situations in which a net operating loss carryforward, a similar tax loss or a tax credit carryforward is not available at the reporting date under the tax law of the jurisdiction or the tax law of the jurisdiction does not require, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit will be presented in the financial statements as a liability and will not be combined with deferred tax assets. This new guidance was effective in first quarter 2014. We adopted the new guidance effective January 1, 2014. The impact of the new guidance upon adoption was not material to our 2014 consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
Summary of Significant Accounting Policies (Tables)	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Estimated Useful Life of Fixed Assets	Depreciation for fixed assets is computed using the straight-line method over the following estimated useful lives:


		Useful Life
	Computer equipment	Three to five years
	Furniture and fixtures	Three to ten years
	Office equipment	Three to ten years
	Software	Three to five years
	Refined fuel plants	Ten years
	Leasehold improvements	Shorter of the lease term or useful life of the asset

Business_Combinations_Tables

Business Combinations (Tables)	12 Months Ended
Business Combinations (Tables)	Dec. 31, 2014
Business Combinations [Abstract]
Acquisition Method for Recording Business Combinations	During 2014, we acquired substantially all of the net assets of the following firms in exchange for our common stock and/or cash. These acquisitions have been accounted for using the acquisition method for recording business combinations (in millions except share data):


	Name and Effective Date		Common			Common		Cash		Accrued		Escrow		Recorded		Total		Maximum
	of Acquisition		Shares			Share		Paid		Liability		Deposited		Earnout		Recorded		Potential
			Issued			Value								Payable		Purchase		Earnout
																Price		Payable
				(000s	)
	Benefit Development			46		$	2	$	0.7	$	—	$	0.1	$	0.6	$	3.4	$	2
	Group, Inc.
	February 1, 2014
	Kent, Kent & Tingle			229			9.1		3.5		—		1.4		3.5		17.5		7.8
	February 1, 2014			229			9.1		3.5		—		1.4		3.5		17.5		7.8
	L&R Benefits, LLC			115			5.3		1.8		—		0.1		1		8.2		6
	March 1, 2014			115			5.3		1.8		—		0.1		1		8.2		6
	Spataro Insurance Agency, Inc. March 1, 2014			47			2		—		—		0.2		0.4		2.6		0.6
	Tudor Risk Services, LLC			—			—		2.1		—		0.2		0.1		2.4		1.3
	March 1, 2014			—			—		2.1		—		0.2		0.1		2.4		1.3
	American Wholesalers Underwriting Ltd April 1, 2014			133			6		5.7		—		0.5		—		12.2		—
	Mike Henry Insurance Brokers Limited April 1, 2014			—			—		9.6		—		1.7		4.2		15.5		5
	Oval Group of Companies (OGC) April 1, 2014			—			—		338.4		—		11.8		—		350.2		—
	Heritage Insurance Management Limited (HIM) May 1, 2014			—			—		33.9		—		3.8		—		37.7		—
	MGA Insurance Group (MGA) May 1, 2014			547			25.1		26.8		—		2.5		11.9		66.3		20
	Shilling Limited May 1, 2014			198			8.9		1.7		—		1.2		1		12.8		8.4
	Sunderland Insurance Services, Inc. May 1, 2014			204			9.2		2.4		—		0.6		—		12.2		—
	Plus Companies, Inc. June 1, 2014			221			9.3		3.4		—		0.8		—		13.5		—
	Tri-State General Insurance Agency, Inc. June 1, 2014			47			2.2		0.6		—		0.1		—		2.9		—
	Crombie/OAMPS (CO) June 16, 2014			—			—		993.1		—		—		—		993.1		—
	Foundation Strategies, Inc. July 1, 2014			46			2		0.7		—		0.1		0.4		3.2		3
	Insurance Point, LLC July 1, 2014			255			11.2		3.9		—		0.5		2.6		18.2		24.4
				(000s	)
	Trip Mate, Inc. July 1, 2014			209		$	8.4	$	3.9	$	—	$	1	$	3.7	$	17	$	12.5
	Noraxis Capital Corporation (NCC) July 2, 2014			—			—		413.3		—		1.9		—		415.2		—
	Cowles & Connell August 1, 2014			331			14.8		4.2		—		0.8		—		19.8		—
	Denman Consulting Services August 1, 2014			40			1.7		0.6		—		0.1		0.3		2.7		1.6
	Minvielle & Chastanet Insurance Brokers August 8, 2014			—			—		5		—		—		3		8		5
	Baker Tilly Financial Management Limited August 29, 2014			185			8.7		2.3		—		0.7		4.7		16.4		5.4
	Benfield Group September 1, 2014			82			3.8		1.1		—		0.1		0.9		5.9		3.5
	Everett James, Inc. September 1, 2014			52			2.4		0.7		—		0.1		0.8		4		4
	Hagedorn & Company September 1, 2014			281			11.5		—		—		1.3		—		12.8		—
	Parmia Pty Ltd. September 1, 2014			—			—		1.7		—		—		1.2		2.9		1.2
	Bennett and Shade Company October 1, 2014			35			1.5		0.5		—		0.2		—		2.2		—
	Insurance Associates, Inc. October 1, 2014			169			7.2		—		—		0.8		1.1		9.1		3
	Forker Company October 31, 2014			24			1.1		0.3		—		0.1		1.6		3.1		2.2
	Discovery Benefit Solutions, Inc. November 1, 2014			115			5.4		—		—		0.1		1.4		6.9		4.5
	Miller-Harrison Insurance Services November 1, 2014			38			1.8		—		—		—		0.6		2.4		1
	SGB-NIA Insurance Brokers (SGB) November 1, 2014			449			18.7		7.2		—		2.9		4.2		33		5.2
	Titan Group LLC November 1, 2014			49			2.4		—		—		0.1		0.4		2.9		2
	Instrat Insurance Brokers December 1, 2014			—			—		16.2		—		—		9.5		25.7		9.5
	O’Gorman & Young Incorporated (OGY) December 1, 2014			554			23.8		—		—		2.7		6.4		32.9		12.5
				(000s	)
	Independent Benefit Services, Inc. (IBS) December 1, 2014			395		$	17.8	$	6.2	$	—	$	0.8	$	1.3	$	26.1	$	14.3
	Affinity Marketing Group December 1, 2014			72			3.1		—		—		0.3		2.2		5.6		5.2
	Blue Holdings Group of Companies December 5, 2014			227			10.9		4.5		—		1.7		1.2		18.3		6.6
	Twenty-one other acquisitions completed in 2014			344			14.8		18.5		—		1.1		10.3		44.7		21.1

				5,739		$	252.1	$	1,914.50	$	—	$	42.4	$	80.5	$	2,289.50	$	198.8

Summary of Estimated Fair Values of Net Assets Acquired	The following is a summary of the estimated fair values of the net assets acquired at the date of each acquisition made in 2014 (in millions):


			OGC			HIM		MGA		CO		NCC		SGB		OGY		IBS		Fifty-Two		Total
																				Other
																				Acquisitions
	Cash		$	23.1		$	2.9	$	0.2	$	26.6	$	10.1	$	—	$	—	$	—	$	5.8	$	68.7
	Other current assets			129.6			4.9		8.9		695.5		73		0.7		2.8		0.5		59.2		975.1
	Fixed assets			2.1			0.3		0.8		17.1		4.9		0.1		0.2		—		4.3		29.8
	Noncurrent assets			—			—		—		7		3.5		0.1		—		—		4.9		15.5
	Goodwill			245.7			14.8		27		619.6		314.9		14.9		25.8		12.7		172.9		1,448.30
	Expiration lists			129.9			20.3		33.2		325.3		178.6		17.8		18.7		13.1		159		895.9
	Non-compete agreements			1			1.3		0.3		4.2		2.6		0.1		0.3		0.2		1.9		11.9
	Trade names			0.6			—		—		4.2		2.2		—		—		—		2.4		9.4

	Total assets acquired			532			44.5		70.4		1,699.50		589.8		33.7		47.8		26.5		410.4		3,454.60

	Current liabilities			129.5			6.8		4.1		490		72.5		0.7		4.1		0.4		63		771.1
	Noncurrent liabilities			52.3			—		—		216.4		102.1		—		10.8		—		12.4		394

	Total liabilities assumed			181.8			6.8		4.1		706.4		174.6		0.7		14.9		0.4		75.4		1,165.10

	Total net assets acquired		$	350.2		$	37.7	$	66.3	$	993.1	$	415.2	$	33	$	32.9	$	26.1	$	335	$	2,289.50

Summary of Unaudited Pro Forma Historical Results	acquisition dates. The following is a summary of the unaudited pro forma historical results, as if these entities had been acquired at January 1, 2013 (in millions, except per share data):


			Year Ended December 31,
			2014			2013
	Total revenues		$	4,984.20		$	3,968.10
	Net earnings			316.1			298.4
	Basic earnings per share			1.94			1.91
	Diluted earnings per share			1.93			1.89
Other Current Assets	4	Other Current Assets
	Major classes of other current assets consist of the following (in millions):


			December 31,
			2014			2013
	Premium finance advances and loans		$	232.6		$	2.3
	Accrued supplemental, direct bill and other receivables			156.3			69
	Refined coal production related receivables			103.5			56.6
	Deferred income taxes - current			102.2			84.9
	Prepaid expenses			72.1			48.5

	Total other current assets		$	666.7		$	261.3

	The premium finance loans represent short-term loans which we make to many of our brokerage related clients and other non-brokerage clients to finance their premiums paid to insurance carriers. These premium finance loans are primarily generated by the Crombie/OAMPS operations which were acquired on June 16, 2014. Financing receivables are carried at amortized cost. Given that these receivables are collateralized, carry a fairly rapid delinquency period of only seven days post payment date, and that contractually the underlying insurance policies will be cancelled within one month of the payment due date, there historically has not been any risk of receiving payment and therefore we do not maintain any significant allowance for losses against this balance.
Summary of Major Classes of Other Current Assets	Major classes of other current assets consist of the following (in millions):


			December 31,
			2014			2013
	Premium finance advances and loans		$	232.6		$	2.3
	Accrued supplemental, direct bill and other receivables			156.3			69
	Refined coal production related receivables			103.5			56.6
	Deferred income taxes - current			102.2			84.9
	Prepaid expenses			72.1			48.5

	Total other current assets		$	666.7		$	261.3

Fixed_Assets_Tables

Fixed Assets (Tables)	12 Months Ended
Fixed Assets (Tables)	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Summary of Fixed Assets	Major classes of fixed assets consist of the following (in millions):


		December 31,
		2014			2013
	Office equipment	$	23		$	16.3
	Furniture and fixtures		89.6			78.3
	Computer equipment		133.9			117.2
	Leasehold improvements		102.9			77.9
	Software		187.8			147.6
	Other		11.5			8.5

			548.7			445.8
	Accumulated depreciation		(353.3	)		(285.4	)

	Net fixed assets	$	195.4		$	160.4

Intangible_Assets_Tables

Intangible Assets (Tables)	12 Months Ended
Intangible Assets (Tables)	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Carrying Amount of Goodwill Allocated by Domestic and Foreign Operations	The carrying amount of goodwill at December 31, 2014 and 2013 allocated by domestic and foreign operations is as follows (in millions):


		Brokerage			Risk			Corporate		Total
		Brokerage			Management			Corporate		Total
	At December 31, 2014
	United States	$	1,652.60		$	20.2		$	—	$	1,672.80
	United Kingdom		818.7			1.9			—		820.6
	Canada		318.5			—			—		318.5
	Australia		336.8			—			—		336.8
	Other foreign, principally New Zealand		300.9			—			—		300.9

	Total goodwill - net	$	3,427.50		$	22.1		$	—	$	3,449.60

	At December 31, 2013
	United States	$	1,449.60		$	20.2		$	—	$	1,469.80
	United Kingdom		582.8			2.1			—		584.9
	Canada		26.8			—			—		26.8
	Australia		37.1			—			—		37.1
	Other foreign		26.6			—			—		26.6

	Total goodwill - net	$	2,122.90		$	22.3		$	—	$	2,145.20

Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill for 2014 and 2013 are as follows (in millions):


		Brokerage			Risk			Corporate		Total
		Brokerage			Management			Corporate		Total
	Balance as of January 1, 2013	$	1,451.40		$	21.3		$	—	$	1,472.70
	Goodwill acquired during the year		664.1			0.9			—		665
	Goodwill adjustments related to appraisals and other acquisition adjustments		3.3			—			—		3.3
	Foreign currency translation adjustments during the year		4.1			0.1			—		4.2

	Balance as of December 31, 2013		2,122.90			22.3			—		2,145.20
	Goodwill acquired during the year		1,448.30			—			—		1,448.30
	Goodwill adjustments related to appraisals and other acquisition adjustments		(8.8	)		—			—		(8.8	)
	Goodwill written-off related to sales of business		(0.6	)		—			—		(0.6	)
	Foreign currency translation adjustments during the year		(134.3	)		(0.2	)		—		(134.5	)

	Balance as of December 31, 2014	$	3,427.50		$	22.1		$	—	$	3,449.60

Major Classes of Amortizable Intangible Assets	Major classes of amortizable intangible assets consist of the following (in millions):


		December 31,
		2014			2013
	Expiration lists	$	2,461.90		$	1,563.50
	Accumulated amortization – expiration lists		(719.3	)		(511.3	)

			1,742.60			1,052.20

	Non-compete agreements		43.2			37.3
	Accumulated amortization – non-compete agreements		(29.5	)		(25.9	)

			13.7			11.4

	Trade names		29.7			22.1
	Accumulated amortization – trade names		(10.0	)		(6.9	)

			19.7			15.2

	Net amortizable assets	$	1,776.00		$	1,078.80

Estimated Aggregate Amortization Expense	Estimated aggregate amortization expense for each of the next five years is as follows (in millions):


	2015	$	214.6
	2016		208.5
	2017		198.7
	2018		187.2
	2019		173.6

	Total	$	982.6

Credit_and_Other_Debt_Agreemen1

Credit and Other Debt Agreements (Tables)	12 Months Ended
Credit and Other Debt Agreements (Tables)	Dec. 31, 2014
Debt Disclosure [Abstract]
Summary of Corporate and Other Debt	The following is a summary of our corporate and other debt (in millions):


		December 31,
		2014		2013
	Note Purchase Agreements:
	Semi-annual payments of interest, fixed rate of 6.26%, balloon due 2014	$	—	$	100
	Semi-annual payments of interest, fixed rate of 6.44%, balloon due 2017		300		300
	Semi-annual payments of interest, fixed rate of 2.80%, balloon due 2018		50		—
	Semi-annual payments of interest, fixed rate of 3.20%, balloon due 2019		50		—
	Semi-annual payments of interest, fixed rate of 5.85%, $50 million due in 2016, 2018 and 2019		150		150
	Semi-annual payments of interest, fixed rate of 3.99%, balloon due 2020		50		50
	Semi-annual payments of interest, fixed rate of 3.48%, balloon due 2020		50		—
	Semi-annual payments of interest, fixed rate of 5.18%, balloon due 2021		75		75
	Semi-annual payments of interest, fixed rate of 3.69%, balloon due 2022		200		200
	Semi-annual payments of interest, fixed rate of 5.49%, balloon due 2023		50		50
	Semi-annual payments of interest, fixed rate of 4.13%, balloon due 2023		200		—
	Semi-annual payments of interest, fixed rate of 4.58%, balloon due 2024		325		—
	Semi-annual payments of interest, fixed rate of 4.31%, balloon due 2025		200		—
	Semi-annual payments of interest, fixed rate of 4.73%, balloon due 2026		175		—
	Semi-annual payments of interest, fixed rate of 4.36%, balloon due 2026		150		—
	Semi-annual payments of interest, fixed rate of 4.98%, balloon due 2029		100		—

	Total Note Purchase Agreements		2,125.00		925

	Credit Agreement:
	Periodic payments of interest and principal, prime or LIBOR plus up to 1.45%, expires September 19, 2018		140		530.5

	Premium Financing Debt Facility - expires June 15, 2016:
	Periodic payments of interest and principal, Interbank rates plus 1.65% for Facility B; plus 0.85% for Facilities C and D
	Facility B
	AUD denominated tranche		95		—
	NZD denominated tranche		17.8		—
	Facility C and D
	AUD denominated tranche		7.7		—
	NZD denominated tranche		7.4		—

	Total Premium Financing Debt Facility		127.9		—

	Total corporate and other debt	$	2,392.90	$	1,455.50

Earnings_per_Share_Tables

Earnings per Share (Tables)	12 Months Ended
Earnings per Share (Tables)	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net EPS	The following table sets forth the computation of basic and diluted net earnings per share (in millions, except per share data):


		Year Ended December 31,
		2014		2013		2012
	Net earnings	$	303.4	$	268.6	$	195

	Weighted average number of common shares outstanding		152.9		128.9		121
	Dilutive effect of stock options using the treasury stock method		1.4		1.6		1.5

	Weighted average number of common and common equivalent shares outstanding		154.3		130.5		122.5

	Basic net earnings per share	$	1.98	$	2.08	$	1.61

	Diluted net earnings per share:	$	1.97	$	2.06	$	1.59

Stock_Option_Plans_Tables

Stock Option Plans (Tables)	12 Months Ended
Stock Option Plans (Tables)	Dec. 31, 2014
Text Block [Abstract]
Black-Scholes Option Pricing Model with Weighted Average	For purposes of expense recognition in 2014, 2013 and 2012, the estimated fair values of the stock option grants are amortized to expense over the options’ vesting period. We estimated the fair value of stock options at the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:


			Year Ended December 31,
			2014				2013				2012
	Expected dividend yield			3	%			3.5	%			4	%
	Expected risk-free interest rate			1.8	%			1.2	%			1.2	%
	Volatility			28.9	%			29.6	%			26.9	%
	Expected life (in years)			5.5				6				5
Stock Option Activity and Related Information	The following is a summary of our stock option activity and related information for 2014, 2013 and 2012 (in millions, except exercise price and year data):


	Year Ended December 31, 2014		Shares				Weighted				Weighted				Aggregate
			Under				Average				Average				Intrinsic
			Option				Exercise				Remaining				Value
							Price				Contractual
											Term
											(in years)
	Beginning balance			8.3			$	31.35
	Granted			1.9				46.86
	Exercised			(1.7	)			28.8
	Forfeited or canceled			(0.1	)			28.36

	Ending balance			8.4			$	35.49				3.96			$	97.2

	Exercisable at end of year			2.6			$	26.91				1.87			$	52.8

	Ending vested and expected to vest			8.3			$	35.38				3.93			$	96.6

	Year Ended December 31, 2013
	Beginning balance			9			$	28.8
	Granted			1.7				39.17
	Exercised			(2.3	)			27.11
	Forfeited or canceled			(0.1	)			26.01

	Ending balance			8.3			$	31.35				3.62			$	129.4

	Exercisable at end of year			3.8			$	27.64				2.15			$	72.5

	Ending vested and expected to vest			8.2			$	31.28				3.59			$	128.3

	Year Ended December 31, 2012
	Beginning balance			10.6			$	27.2
	Granted			1.4				35.71
	Exercised			(2.8	)			26.14
	Forfeited or canceled			(0.2	)			29.46

	Ending balance			9			$	28.8				3.41			$	53.9

	Exercisable at end of year			5.1			$	27.5				2.52			$	36.3

	Ending vested and expected to vest			8.9			$	28.76				3.39			$	53.8

Other Information Regarding Stock Options Outstanding and Exercisable	Other information regarding stock options outstanding and exercisable at December 31, 2014 is summarized as follows (in millions, except exercise price and year data):


					Options Outstanding												Options Exercisable
	Range of Exercise Prices				Number				Weighted				Weighted				Number		Weighted
					Outstanding				Average				Average				Exercisable		Average
									Remaining				Exercise						Exercise
									Contractual				Price						Price
									Term
									(in years)
	$	21.28 - $ 27.25				2.3				1.59			$	25.78				1.9	$	25.76
		27.35 - 35.71				2.5				3.59				33.18				0.7		29.83
		35.95 - 46.16				1.7				5.2				39.19				—		—
		46.87 - 46.87				1.9				6.19				46.87				—		—

	$	21.28 - $ 46.87				8.4				3.96			$	35.49				2.6	$	26.91

Restricted_Stock_Performance_S1

Restricted Stock, Performance Share and Cash Awards (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Schedule of Restricted Stock Awards Vesting Periods	The vesting periods of the 2014, 2013 and 2012 restricted stock awards are as follows (in actual shares):



		Shares Granted
	Vesting Period	2014		2013		2012
	One year		19,250		19,375		20,000
	Three years		33,741		—		—
	Four years		323,550		345,000		332,000
	Five years		—		5,600		9,400

	Total shares granted		376,541		369,975		361,400

Retirement_Plans_Tables

Retirement Plans (Tables)	12 Months Ended
Retirement Plans (Tables)	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Reconciliation of Balances of Pension Benefit Obligation and Fair Value of Plan Assets	A reconciliation of the beginning and ending balances of the pension benefit obligation and fair value of plan assets and the funded status of the plan is as follows (in millions):



		Year Ended December 31,
		2014			2013
	Change in pension benefit obligation:
	Benefit obligation at beginning of year	$	272.5		$	292
	Service cost		0.7			0.6
	Interest cost		12.7			11.7
	Net actuarial loss (gain)		56.8			(22.4	)
	Partial plan settlement loss		(16.7	)		—
	Benefits paid		(54.0	)		(9.4	)

	Benefit obligation at end of year	$	272		$	272.5

	Change in plan assets:
	Fair value of plan assets at beginning of year	$	254.9		$	227.4
	Actual return on plan assets		16.3			30.6
	Contributions by the company		—			6.3
	Benefits paid		(54.0	)		(9.4	)

	Fair value of plan assets at end of year	$	217.2		$	254.9

	Funded status of the plan (underfunded)	$	(54.8	)	$	(17.6	)

	Amounts recognized in the consolidated balance sheet consist of:
	Noncurrent liabilities - accrued benefit liability	$	(54.8	)	$	(17.6	)
	Accumulated other comprehensive loss - net actuarial loss		75.2			47

	Net amount included in retained earnings	$	20.4		$	29.4

Components of Net Periodic Pension Benefit Cost and Other Changes in Plan Assets and Obligations Recognized in Earnings and Other Comprehensive Earnings	The components of the net periodic pension benefit cost for the plan and other changes in plan assets and obligations recognized in earnings and other comprehensive earnings consist of the following (in millions):



		Year Ended December 31,
		2014			2013			2012
	Net periodic pension cost (earnings):
	Service cost	$	0.7		$	0.6		$	0.4
	Interest cost on benefit obligation		12.7			11.7			11.8
	Expected return on plan assets		(18.7	)		(17.0	)		(15.2	)
	Amortization of net loss		2.3			7.9			7.2
	Settlement		12			—			—

	Net periodic benefit cost (earnings)		9			3.2			4.2

	Other changes in plan assets and obligations recognized in other comprehensive earnings:
	Net loss (gain) incurred		42.5			(36.0	)		10.6
	Settlement recognition		(12.0	)		—			—
	Amortization of net loss		(2.3	)		(7.9	)		(7.2	)

	Total recognized in other comprehensive loss (earnings)		28.2			(43.9	)		3.4

	Total recognized in net periodic pension cost (earnings) and other comprehensive loss (earnings)	$	37.2		$	(40.7	)	$	7.6

	Estimated amortization for the following year:
	Amortization of net loss	$	6		$	2.4		$	7.7



Weighted Average Assumptions of Pension Benefit Obligation and Net Periodic Pension Benefit Cost	The following weighted average assumptions were used at December 31 in determining the plan’s pension benefit obligation:



		December 31,
		2014			2013
	Discount rate		4	%		4.75	%
	Weighted average expected long-term rate of return on plan assets		7.5	%		7.5	%

	The following weighted average assumptions were used at January 1 in determining the plan’s net periodic pension benefit cost:



		Year Ended December 31,
		2014			2013			2012
	Discount rate		4.75	%		4	%		4.5	%
	Weighted average expected long-term rate of return on plan assets		7.5	%		7.5	%		7.5	%
Schedule of Benefit Payments Expected to be Paid by Plan	The following benefit payments are expected to be paid by the plan (in millions):



	2015	$	10.8
	2016		11.3
	2017		11.8
	2018		12.3
	2019		12.9
	Years 2020 to 2024		73.3
Summary of Plans Weighted Average Asset Allocations	The following is a summary of the plan’s weighted average asset allocations at December 31 by asset category:



		December 31,
	Asset Category	2014			2013
	Equity securities		65	%		69	%
	Debt securities		26	%		24	%
	Real estate		9	%		7	%

	Total		100	%		100	%

Summary of Plan's Assets Carried at Fair Value	The following is a summary of the plan’s assets carried at fair value as of December 31 by level within the fair value hierarchy (in millions):



		December 31,
	Fair Value Hierarchy	2014			2013
	Level 1	$	—		$	—
	Level 2		116.1			158.8
	Level 3		101.1			96.1

	Total fair value	$	217.2		$	254.9

Reconciliation of Beginning and Ending Balances for Level 3 Assets of Plan Measured at Fair Value	The following is a reconciliation of the beginning and ending balances for the Level 3 assets of the plan measured at fair value (in millions):



		Year Ended December 31,
		2014			2013
	Fair value at January 1	$	96.1		$	91.1
	Settlements		—			—
	Unrealized gains		5			5

	Fair value at December 31	$	101.1		$	96.1

Investments_Tables

Investments (Tables)	12 Months Ended
Investments (Tables)	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Investments Reported in Other Current and Non-Current Assets	The following is a summary of our investments and the related funding commitments (in millions):


		December 31, 2014				December 31,
				Funding		2013
		Assets		Commitments		Assets
	Chem-Mod LLC	$	4	$	—	$	4
	Chem-Mod International LLC		2		—		2
	C-Quest Technology LLC and C-Quest Technologies International LLC		—		—		2
	Clean-coal investments:
	Controlling interest in five limited liability companies that own fourteen 2009 Era Clean Coal Plants		17.3		—		18.3
	Non-controlling interest in one limited liability companies that owns one 2011 Era Clean Coal Plants		1		—		1.1
	Controlling interest in thirteen limited liability companies that own nineteen 2011 Era Clean Coal Plants		54.5		—		59.3
	Other investments		3.2		2.9		3.7

	Total investments	$	82	$	2.9	$	90.4

Commitments_Contingencies_and_1

Commitments, Contingencies and Off-Balance Sheet Arrangements (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Contractual Obligations	Our future minimum cash payments, including interest, associated with our contractual obligations pursuant to the note purchase agreements and Credit Agreement, Premium Financing Debt Facility, operating leases and purchase commitments at December 31, 2014 were as follows (in millions):


			Payments Due by Period
	Contractual Obligations		2015			2016			2017			2018			2019		Thereafter		Total
	Note purchase agreements		$	—		$	50		$	300		$	100		$	100	$	1,575.00	$	2,125.00
	Credit Agreement			140			—			—			—			—		—		140
	Premium Financing Debt Facility			127.9			—			—			—			—		—		127.9
	Interest on debt			100.9			100.4			97.5			77.5			73.2		323.9		773.4

	Total debt obligations			368.8			150.4			397.5			177.5			173.2		1,898.90		3,166.30
	Operating lease obligations			99			81.7			68.7			49.8			38.8		131.3		469.3
	Less sublease arrangements			(1.4	)		(0.7	)		(0.3	)		(0.1	)		—		—		(2.5	)
	Outstanding purchase obligations			29.7			5.4			0.9			0.3			—		—		36.3

	Total contractual obligations		$	496.1		$	236.8		$	466.8		$	227.5		$	212	$	2,030.20	$	3,669.40

Off-Balance Sheet Commitments	Off-Balance Sheet Commitments - Our total unrecorded commitments associated with outstanding letters of credit, financial guarantees and funding commitments at December 31, 2014 were as follows (in millions):


																			Total
			Amount of Commitment Expiration by Period																Amounts
	Off-Balance Sheet Commitments		2015			2016			2017			2018			2019		Thereafter		Committed
	Letters of credit		$	—		$	—		$	—		$	—		$	—	$	22.6	$	22.6
	Financial guarantees			0.8			0.8			0.8			0.8			0.9		16.5		20.6
	Funding commitments			—			—			—			—			—		2.9		2.9

	Total commitments		$	0.8		$	0.8		$	0.8		$	0.8		$	0.9	$	42	$	46.1

Outstanding Letters of Credit and Funding Commitments	Our commitments associated with outstanding letters of credit, financial guarantees and funding commitments at December 31, 2014 were as follows (all dollar amounts in table are in millions):


	Description, Purpose and Trigger		Collateral		Compensation	Maximum			Liability
	Description, Purpose and Trigger		Collateral		to Us	Exposure			Recorded
	Venture capital funds
	Funding commitment to two funds - $1.5 million and $1.4 million expire in 2019 and 2023, respectively Trigger - Agreed conditions met		None		None	$	2.9		$	—
	Other
	Credit support under letters of credit for deductibles due by us on our own insurance coverages - expires after 2019 Trigger - We do not reimburse the insurance companies for deductibles the insurance companies advance on behalf of us		None		None		11.3			9.7
	Credit enhancement under letters of credit for our captive insurance operations to meet minimum statutory capital requirements - expires after 2019 Trigger - Dissolution or catastrophic financial results of the operation		None		Reimbursement		6.3			—
			None		of LOC fees		6.3			—
	Credit support under letters of credit for clients’ claim funds held by our Bermuda captive insurance operation in a fiduciary capacity - expires after 2019 Trigger - Investments fall below prescribed levels		None		Reimbursement		5			—
			None		of LOC fees		5			—
	Financial guarantee of a mortgage loan to a U.K.-based employee - expires when mortgage balance is reduced to $6.4 million Trigger - Default on mortgage payments		-1		None		9.1			—
	Financial guarantees of loans to 37 Canadian-based employees - expires when loan balances are reduced to zero from 2017 through 2029 - Principal and interest payments are paid quarterly Trigger - Default on loan payments		-2		None		11.5			—

						$	46.1		$	9.7


	-1	The guarantee has no collateral. The mortgage loan has a lien on real property with an appraised value of approximately $11.0 million.
	-2	The guarantees are collateralized by shares in minority holdings of our Canadian operating companies.

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Components of Earnings Before Income Taxes and Provision for Income Taxes	Significant components of earnings before income taxes and the provision for income taxes are as follows (in millions):


		Year Ended December 31,
		2014			2013			2012
	Earnings before income taxes:
	Domestic	$	264.9		$	230.8		$	234.7
	Foreign, principally Australia, Canada, New Zealand and the U.K.		2.5			43.7			10.6

		$	267.4		$	274.5		$	245.3

	Provision (benefit) for income taxes:
	Federal:
	Current	$	38.8		$	29		$	45.4
	Deferred		(96.6	)		(47.7	)		(14.6	)

			(57.8	)		(18.7	)		30.8

	State and local:
	Current		19.5			10.6			17.3
	Deferred		(1.1	)		(0.6	)		(2.9	)

			18.4			10			14.4

	Foreign:
	Current		30.5			28.5			8.7
	Deferred		(27.1	)		(13.9	)		(3.6	)

			3.4			14.6			5.1

	Total provision (benefit) for income taxes	$	(36.0	)	$	5.9		$	50.3

Reconciliation of Provision for Income Taxes with Federal Statutory Income Tax Rate	A reconciliation of the provision for income taxes with the U.S. Federal statutory income tax rate is as follows (in millions, except percentages):


		Year Ended December 31,
		2014						2013						2012
		Amount			% of			Amount			% of			Amount			% of
					Pretax						Pretax						Pretax
					Earnings						Earnings						Earnings
	Federal statutory rate	$	93.6			35		$	96.1			35		$	85.9			35
	State income taxes - net of Federal benefit		12			4.5			6.5			2.4			9.4			3.8
	Foreign taxes		0.8			0.3			(0.8	)		(0.3	)		0.9			0.4
	Alternative energy, foreign and other tax credits		(145.5	)		(54.4	)		(93.8	)		(34.2	)		(45.3	)		(18.5	)
	Foreign dividends and other permanent differences		(6.1	)		(2.3	)		(2.5	)		(0.9	)		(2.7	)		(1.1	)
	Nondeductible employee compensation		5.4			2			—			—			—			—
	Changes in unrecognized tax benefits		2.4			0.9			1.5			0.5			0.6			0.2
	Change in valuation allowance		—			—			0.5			0.2			0.3			0.1
	Other		1.4			0.5			(1.6	)		(0.6	)		1.2			0.6

	Provision (benefit) for income taxes	$	(36.0	)		(13.5	)	$	5.9			2.1		$	50.3			20.5

Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows (in millions):


		December 31,
		2014			2013
	Gross unrecognized tax benefits at January 1	$	9.2		$	6.7
	Increases in tax positions for current year		2.6			2.9
	Settlements		—			—
	Lapse in statute of limitations		(1.0	)		(1.4	)
	Increases in tax positions for prior years		1.7			2.3
	Decreases in tax positions for prior years		—			(1.3	)

	Gross unrecognized tax benefits at December 31	$	12.5		$	9.2

Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities are as follows (in millions):


		December 31,
		2014			2013
	Deferred tax assets:
	Alternative minimum tax and other credit carryforwards	$	233.4		$	147.4
	Accrued and unfunded compensation and employee benefits		166.9			136.6
	Amortizable intangible assets		66.7			12.5
	Compensation expense related to stock options		14.7			14.2
	Accrued liabilities		31			30.2
	Accrued pension liability		24.3			9.2
	Investments		10			9
	Net operating loss carryforwards		10			11.9
	Deferred rent liability		8.5			8.2
	Other		4.8			6.8

	Total deferred tax assets		570.3			386
	Valuation allowance for deferred tax assets		(75.5	)		(21.3	)

	Deferred tax assets		494.8			364.7

	Deferred tax liabilities:
	Nondeductible amortizable intangible assets		338.7			184
	Investment-related partnerships		26.6			13.2
	Depreciable fixed assets		8.8			5.2
	Other prepaid items		4.3			4.7
	Accrued liabilities		—			2.4

	Total deferred tax liabilities		378.4			209.5

	Net deferred tax assets	$	116.4		$	155.2

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Earnings (Tables)	12 Months Ended
Accumulated Other Comprehensive Earnings (Tables)	Dec. 31, 2014
Equity [Abstract]
Schedule of Accumulated Comprehensive Earnings (Loss)	The after-tax components of our accumulated comprehensive earnings (loss) consist of the following:


		Pension			Foreign			Fair Value			Accumulated
		Liability			Currency			of Derivative			Comprehensive
					Translation			Instruments			Earnings (Loss)
	Balance as of January 1, 2012	$	(49.0	)	$	4.4		$	(2.6	)	$	(47.2	)
	Net change in period		(3.4	)		16.1			1.7			14.4

	Balance as of December 31, 2012		(52.4	)		20.5			(0.9	)		(32.8	)
	Net change in period		26.8			1.6			1.8			30.2

	Balance as of December 31, 2013		(25.6	)		22.1			0.9			(2.6	)
	Net change in period		(18.6	)		(238.4	)		(1.0	)		(258.0	)

	Balance as of December 31, 2014	$	(44.2	)	$	(216.3	)	$	(0.1	)	$	(260.6	)

Quarterly_Operating_Results_un1

Quarterly Operating Results (unaudited) (Tables)	12 Months Ended
Quarterly Operating Results (unaudited) (Tables)	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Operating Results	Quarterly operating results for 2014 and 2013 were as follows (in millions, except per share data):


		1st		2nd		3rd		4th
	2014
	Total revenues	$	915	$	1,179.30	$	1,286.80	$	1,245.40
	Total expenses		868.7		1,072.20		1,199.10		1,219.10

	Earnings before income taxes	$	46.3	$	107.1	$	87.7	$	26.3

	Net earnings	$	49.3	$	109	$	93.6	$	51.5

	Basic net earnings per share:	$	0.37	$	0.71	$	0.58	$	0.32

	Diluted net earnings per share:	$	0.36	$	0.7	$	0.58	$	0.31

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
Segment Information (Tables)	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of Segment Reporting Information by Segment	Financial information relating to our segments for 2014, 2013 and 2012 is as follows (in millions):


	Year Ended December 31, 2014		Brokerage			Risk			Corporate				Total
	Year Ended December 31, 2014		Brokerage			Management			Corporate				Total
	Revenues:
	Commissions		$	2,083.00		$	—		$	—			$	2,083.00
	Fees			595			663.3			—				1,258.30
	Supplemental commissions			104			—			—				104
	Contingent commissions			84.7			—			—				84.7
	Investment income			40.3			1			—				41.3
	Gains on books of business sales and other			7.3			—			—				7.3
	Revenue from clean coal activities			—			—			1,029.50				1,029.50
	Other - net gain			—			—			18.4				18.4

	Total revenues			2,914.30			664.3			1,047.90				4,626.50

	Compensation			1,715.70			401.6			50.3				2,167.60
	Operating			534.1			173.3			59.8				767.2
	Cost of revenues from clean coal activities			—			—			1,058.90				1,058.90
	Interest			—			—			89				89
	Depreciation			44.7			20.9			3.8				69.4
	Amortization			186.7			2.8			—				189.5
	Change in estimated acquisition earnout payables			17.5			—			—				17.5

	Total expenses			2,498.70			598.6			1,261.80				4,359.10

	Earnings (loss) before income taxes			415.6			65.7			(213.9	)			267.4
	Provision (benefit) for income taxes			151.8			24.5			(212.3	)			(36.0	)

	Net earnings		$	263.8		$	41.2		$	(1.6	)		$	303.4

	Net foreign exchange gain (loss)		$	1.1		$	—		$	(0.6	)		$	0.5
	Revenues:
	United States		$	1,891.30		$	514.7		$	1,048.90			$	3,454.90
	United Kingdom			697.1			29.3			—				726.4
	Australia			128.9			114.2			—				243.1
	Canada			81.8			3.2			—				85
	Other foreign, principally New Zealand			115.2			2.9			(1.0	)			117.1

	Total revenues		$	2,914.30		$	664.3		$	1,047.90			$	4,626.50

	At December 31, 2014
	Identifiable assets:
	United States		$	3,584.30		$	430.3		$	1,032.00			$	5,046.60
	United Kingdom			2,376.40			74			—				2,450.40
	Australia			639.2			2.8			—				642
	Canada			992.2			39			—				1,031.20
	Other foreign, principally New Zealand			821.3			1.6			16.9				839.8

	Total identifiable assets		$	8,413.40		$	547.7		$	1,048.90			$	10,010.00

	Goodwill - net		$	3,427.50		$	22.1		$	—			$	3,449.60
	Amortizable intangible assets - net			1,761.20			14.8			—				1,776.00


	Year Ended December 31, 2013		Brokerage			Risk			Corporate				Total
	Year Ended December 31, 2013		Brokerage			Management			Corporate				Total
	Revenues:
	Commissions		$	1,553.10		$	—		$	—			$	1,553.10
	Fees			450.5			609			—				1,059.50
	Supplemental commissions			77.3			—			—				77.3
	Contingent commissions			52.1			—			—				52.1
	Investment income			6.1			2			—				8.1
Gains on books of business sales and other			5.2			—			—				5.2
Revenue from clean coal activities			—			—			412.5				412.5
Other - net gain			—			—			11.8				11.8

Total revenues			2,144.30			611			424.3				3,179.60

Compensation			1,290.40			370.5			24.1				1,685.00
Operating			369.9			146			36.5				552.4
Cost of revenues from clean coal activities			—			—			437.3				437.3
Interest			—			—			50.1				50.1
Depreciation			31.1			19.4			2.9				53.4
Amortization			122.7			2.5			—				125.2
Change in estimated acquisition earnout payables			2.6			(0.9	)		—				1.7

Total expenses			1,816.70			537.5			550.9				2,905.10

Earnings (loss) before income taxes			327.6			73.5			(126.6	)			274.5
Provision (benefit) for income taxes			122.8			27.3			(144.2	)			5.9

Net earnings		$	204.8		$	46.2		$	17.6			$	268.6

Net foreign exchange gain (loss)		$	0.6		$	—		$	(0.4	)		$	0.2
Revenues:
United States		$	1,644.80		$	473.5		$	424.3			$	2,542.60
United Kingdom			400.5			27.4			—				427.9
Australia			47.1			105.5			—				152.6
Canada			29.5			3.1			—				32.6
Other foreign, principally Bermuda			22.4			1.5			—				23.9

Total revenues		$	2,144.30		$	611		$	424.3			$	3,179.60

At December 31, 2013
Identifiable assets:
United States		$	3,219.60		$	419		$	783.8			$	4,422.40
United Kingdom			1,819.50			58.8			—				1,878.30
Australia			214.3			63.6			—				277.9
Canada			107.3			1.5			—				108.8
Other foreign, principally Bermuda			162			1.8			9.3				173.1

Total identifiable assets		$	5,522.70		$	544.7		$	793.1			$	6,860.50

Goodwill - net		$	2,122.90		$	22.3		$	—			$	2,145.20
Amortizable intangible assets - net			1,061.60			17.2			—				1,078.80


Year Ended December 31, 2012		Brokerage			Risk			Corporate				Total
Year Ended December 31, 2012		Brokerage			Management			Corporate				Total
Revenues:
Commissions		$	1,302.50		$	—		$	—			$	1,302.50
Fees			403.2			568.5			—				971.7
Supplemental commissions			67.9			—			—				67.9
Contingent commissions			42.9			—			—				42.9
Investment income			7.2			3.2			—				10.4
Gains on books of business sales and other			3.9			—			—				3.9
Revenue from clean coal activities			—			—			119.6				119.6
Other - net gain			—			—			1.4				1.4

Total revenues			1,827.60			571.7			121				2,520.30

Compensation			1,131.60			347			14.8				1,493.40
Operating			312.7			137.7			32.8				483.2
Cost of revenues from clean coal activities			—			—			111.6				111.6
Interest			—			—			43				43
Depreciation			24.7			16			0.7				41.4
Amortization			96.2			2.8			—				99
Change in estimated acquisition earnout payables			3.6			(0.2	)		—				3.4

Total expenses			1,568.80			503.3			202.9				2,275.00

Earnings (loss) before income taxes			258.8			68.4			(81.9	)			245.3
Provision (benefit) for income taxes			103			25.9			(78.6	)			50.3

Net earnings (loss)		$	155.8		$	42.5		$	(3.3	)		$	195

Net foreign exchange loss		$	(1.6	)	$	(0.1	)	$	(0.2	)		$	(1.9	)
Revenues:
United States		$	1,431.60		$	453.5		$	121			$	2,006.10
United Kingdom			317.8			28.2			—				346
Australia			35.1			86.3			—				121.4
Canada			28.9			3.2			—				32.1
Other foreign, principally Bermuda			14.2			0.5			—				14.7

Total revenues		$	1,827.60		$	571.7		$	121			$	2,520.30

At December 31, 2012
Identifiable assets:
United States		$	2,637.10		$	390.9		$	647.9			$	3,675.90
United Kingdom			1,117.60			52.4			—				1,170.00
Australia			208.4			52.1			—				260.5
Canada			100.7			1.7			—				102.4
Other foreign, principally Bermuda			133			1.5			9				143.5

Total identifiable assets		$	4,196.80		$	498.6		$	656.9			$	5,352.30

Goodwill - net		$	1,451.40		$	21.3		$	—			$	1,472.70
Amortizable intangible assets - net			791.6			18			—				809.6

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail)

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

Sep. 01, 2013

Dec. 31, 2014

USD ($)

AUD

Employee Stock Purchase Plan [Member]

Expiration Lists [Member]

Non-Compete Agreements [Member]

Trade Names [Member]

Country

Contract

USD ($)

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Segment

Contract

Significant Accounting Policies [Line Items]

Number of countries in which the company has operations

Number of countries in which the company does business through a network of correspondent brokers and consultants

140

Number of reportable segments

Percentage of ownership interest

50.00%

99.00%

Percentage of variable ownership interest

50.00%

Fee revenue generation period, years

1 year

Allowances for estimated policy cancellations

$6,800,000

$4,200,000

Allowance for doubtful accounts

10,700,000

6,700,000

Maturity period of short-term investments

90 days or less

Gain on foreign currency derivative investment contract

1,900,000

2,600,000

Number of foreign currency derivative investment contracts

Foreign currency derivative investment contract

400,000,000

Outstanding loan receivable

232,600,000

2,300,000

Estimated useful lives of intangibles assets, years

3 years

15 years

3 years

5 years

15 years

Write-off of amortizable intangible assets

1,800,000

2,200,000

3,500,000

Number of shares authorized

4,000,000

Percentage of employees contribution

15.00%

Purchase price of common stock, percentage

95.00%

Aggregate fair market value of shares purchased

$25,000

Maximum number of shares purchased by employees

200,000

2,000

Shares available for grant

300,000

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Summery of Estimated Useful Lives of Fixed Assets (Detail)	12 Months Ended
	Dec. 31, 2014
Refined Fuel Plants [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	10 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives, years	Shorter of the lease term or useful life of the asset
Minimum [Member] \| Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	3 years
Minimum [Member] \| Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	3 years
Minimum [Member] \| Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	3 years
Minimum [Member] \| Software [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	3 years
Maximum [Member] \| Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	5 years
Maximum [Member] \| Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	10 years
Maximum [Member] \| Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	10 years
Maximum [Member] \| Software [Member]
Property, Plant and Equipment [Line Items]
Useful life, years	5 years

Business_Combinations_Acquisit

Business Combinations - Acquisition Method for Recording Business Combinations (Detail) (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Dec. 31, 2014
Business Acquisition [Line Items]
Common Shares Issued	5,739
Common Share Value	$252.10
Cash Paid	1,914.50
Accrued Liability	0
Escrow Deposited	42.4
Recorded Earnout Payable	80.5
Total Recorded Purchase Price	2,289.50
Maximum Potential Earnout Payable	198.8
Benefit Development Group, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	46
Common Share Value	2
Cash Paid	0.7
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0.6
Total Recorded Purchase Price	3.4
Maximum Potential Earnout Payable	2
Kent, Kent & Tingle [Member]
Business Acquisition [Line Items]
Common Shares Issued	229
Common Share Value	9.1
Cash Paid	3.5
Accrued Liability	0
Escrow Deposited	1.4
Recorded Earnout Payable	3.5
Total Recorded Purchase Price	17.5
Maximum Potential Earnout Payable	7.8
L&R Benefits, LLC [Member]
Business Acquisition [Line Items]
Common Shares Issued	115
Common Share Value	5.3
Cash Paid	1.8
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	1
Total Recorded Purchase Price	8.2
Maximum Potential Earnout Payable	6
Spataro Insurance Agency, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	47
Common Share Value	2
Cash Paid	0
Accrued Liability	0
Escrow Deposited	0.2
Recorded Earnout Payable	0.4
Total Recorded Purchase Price	2.6
Maximum Potential Earnout Payable	0.6
Tudor Risk Services, LLC [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	2.1
Accrued Liability	0
Escrow Deposited	0.2
Recorded Earnout Payable	0.1
Total Recorded Purchase Price	2.4
Maximum Potential Earnout Payable	1.3
American Wholesalers Underwriting Ltd [Member]
Business Acquisition [Line Items]
Common Shares Issued	133
Common Share Value	6
Cash Paid	5.7
Accrued Liability	0
Escrow Deposited	0.5
Recorded Earnout Payable	0
Total Recorded Purchase Price	12.2
Maximum Potential Earnout Payable	0
Mike Henry Insurance Brokers Limited [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	9.6
Accrued Liability	0
Escrow Deposited	1.7
Recorded Earnout Payable	4.2
Total Recorded Purchase Price	15.5
Maximum Potential Earnout Payable	5
Oval Group of Companies (OGC) [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	338.4
Accrued Liability	0
Escrow Deposited	11.8
Recorded Earnout Payable	0
Total Recorded Purchase Price	350.2
Maximum Potential Earnout Payable	0
Heritage Insurance Management Limited (HIM) [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	33.9
Accrued Liability	0
Escrow Deposited	3.8
Recorded Earnout Payable	0
Total Recorded Purchase Price	37.7
Maximum Potential Earnout Payable	0
MGA Insurance Group (MGA) [Member]
Business Acquisition [Line Items]
Common Shares Issued	547
Common Share Value	25.1
Cash Paid	26.8
Accrued Liability	0
Escrow Deposited	2.5
Recorded Earnout Payable	11.9
Total Recorded Purchase Price	66.3
Maximum Potential Earnout Payable	20
Shilling Limited [Member]
Business Acquisition [Line Items]
Common Shares Issued	198
Common Share Value	8.9
Cash Paid	1.7
Accrued Liability	0
Escrow Deposited	1.2
Recorded Earnout Payable	1
Total Recorded Purchase Price	12.8
Maximum Potential Earnout Payable	8.4
Sunderland Insurance Services, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	204
Common Share Value	9.2
Cash Paid	2.4
Accrued Liability	0
Escrow Deposited	0.6
Recorded Earnout Payable	0
Total Recorded Purchase Price	12.2
Maximum Potential Earnout Payable	0
Plus Companies, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	221
Common Share Value	9.3
Cash Paid	3.4
Accrued Liability	0
Escrow Deposited	0.8
Recorded Earnout Payable	0
Total Recorded Purchase Price	13.5
Maximum Potential Earnout Payable	0
Tri-State General Insurance Agency, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	47
Common Share Value	2.2
Cash Paid	0.6
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0
Total Recorded Purchase Price	2.9
Maximum Potential Earnout Payable	0
Crombie/OAMPS (CO) [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	993.1
Accrued Liability	0
Escrow Deposited	0
Recorded Earnout Payable	0
Total Recorded Purchase Price	993.1
Maximum Potential Earnout Payable	0
Foundation Strategies, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	46
Common Share Value	2
Cash Paid	0.7
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0.4
Total Recorded Purchase Price	3.2
Maximum Potential Earnout Payable	3
Insurance Point, LLC (IPL) [Member]
Business Acquisition [Line Items]
Common Shares Issued	255
Common Share Value	11.2
Cash Paid	3.9
Accrued Liability	0
Escrow Deposited	0.5
Recorded Earnout Payable	2.6
Total Recorded Purchase Price	18.2
Maximum Potential Earnout Payable	24.4
Trip Mate, Inc. (TMI) [Member]
Business Acquisition [Line Items]
Common Shares Issued	209
Common Share Value	8.4
Cash Paid	3.9
Accrued Liability	0
Escrow Deposited	1
Recorded Earnout Payable	3.7
Total Recorded Purchase Price	17
Maximum Potential Earnout Payable	12.5
Noraxis Capital Corporation (NCC) [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	413.3
Accrued Liability	0
Escrow Deposited	1.9
Recorded Earnout Payable	0
Total Recorded Purchase Price	415.2
Maximum Potential Earnout Payable	0
Cowles & Connell (CC) [Member]
Business Acquisition [Line Items]
Common Shares Issued	331
Common Share Value	14.8
Cash Paid	4.2
Accrued Liability	0
Escrow Deposited	0.8
Recorded Earnout Payable	0
Total Recorded Purchase Price	19.8
Maximum Potential Earnout Payable	0
Denman Consulting Services [Member]
Business Acquisition [Line Items]
Common Shares Issued	40
Common Share Value	1.7
Cash Paid	0.6
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0.3
Total Recorded Purchase Price	2.7
Maximum Potential Earnout Payable	1.6
Minvielle & Chastanet Insurance Brokers [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	5
Accrued Liability	0
Escrow Deposited	0
Recorded Earnout Payable	3
Total Recorded Purchase Price	8
Maximum Potential Earnout Payable	5
Baker Tilly Financial Management Limited [Member]
Business Acquisition [Line Items]
Common Shares Issued	185
Common Share Value	8.7
Cash Paid	2.3
Accrued Liability	0
Escrow Deposited	0.7
Recorded Earnout Payable	4.7
Total Recorded Purchase Price	16.4
Maximum Potential Earnout Payable	5.4
Benfield Group [Member]
Business Acquisition [Line Items]
Common Shares Issued	82
Common Share Value	3.8
Cash Paid	1.1
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0.9
Total Recorded Purchase Price	5.9
Maximum Potential Earnout Payable	3.5
Everett James, Inc. [Member]
Business Acquisition [Line Items]
Common Shares Issued	52
Common Share Value	2.4
Cash Paid	0.7
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0.8
Total Recorded Purchase Price	4
Maximum Potential Earnout Payable	4
Hagedorn & Company [Member]
Business Acquisition [Line Items]
Common Shares Issued	281
Common Share Value	11.5
Cash Paid	0
Accrued Liability	0
Escrow Deposited	1.3
Recorded Earnout Payable	0
Total Recorded Purchase Price	12.8
Maximum Potential Earnout Payable	0
Parmia Pty Ltd. [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	1.7
Accrued Liability	0
Escrow Deposited	0
Recorded Earnout Payable	1.2
Total Recorded Purchase Price	2.9
Maximum Potential Earnout Payable	1.2
Bennett and Shade Company [Member]
Business Acquisition [Line Items]
Common Shares Issued	35
Common Share Value	1.5
Cash Paid	0.5
Accrued Liability	0
Escrow Deposited	0.2
Recorded Earnout Payable	0
Total Recorded Purchase Price	2.2
Maximum Potential Earnout Payable	0
Insurance Associates Inc [Member]
Business Acquisition [Line Items]
Common Shares Issued	169
Common Share Value	7.2
Cash Paid	0
Accrued Liability	0
Escrow Deposited	0.8
Recorded Earnout Payable	1.1
Total Recorded Purchase Price	9.1
Maximum Potential Earnout Payable	3
Forker Company [Member]
Business Acquisition [Line Items]
Common Shares Issued	24
Common Share Value	1.1
Cash Paid	0.3
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	1.6
Total Recorded Purchase Price	3.1
Maximum Potential Earnout Payable	2.2
Discovery Benefit Solutions Inc [Member]
Business Acquisition [Line Items]
Common Shares Issued	115
Common Share Value	5.4
Cash Paid	0
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	1.4
Total Recorded Purchase Price	6.9
Maximum Potential Earnout Payable	4.5
Miller Harrison Insurance Services [Member]
Business Acquisition [Line Items]
Common Shares Issued	38
Common Share Value	1.8
Cash Paid	0
Accrued Liability	0
Escrow Deposited	0
Recorded Earnout Payable	0.6
Total Recorded Purchase Price	2.4
Maximum Potential Earnout Payable	1
SGB-NIA Insurance Brokers (SGB) [Member]
Business Acquisition [Line Items]
Common Shares Issued	449
Common Share Value	18.7
Cash Paid	7.2
Accrued Liability	0
Escrow Deposited	2.9
Recorded Earnout Payable	4.2
Total Recorded Purchase Price	33
Maximum Potential Earnout Payable	5.2
Titan Group LLC [Member]
Business Acquisition [Line Items]
Common Shares Issued	49
Common Share Value	2.4
Cash Paid	0
Accrued Liability	0
Escrow Deposited	0.1
Recorded Earnout Payable	0.4
Total Recorded Purchase Price	2.9
Maximum Potential Earnout Payable	2
Instrat Insurance Brokers [Member]
Business Acquisition [Line Items]
Common Shares Issued	0
Common Share Value	0
Cash Paid	16.2
Accrued Liability	0
Escrow Deposited	0
Recorded Earnout Payable	9.5
Total Recorded Purchase Price	25.7
Maximum Potential Earnout Payable	9.5
O Gorman & Young Incorporated (OGY) [Member]
Business Acquisition [Line Items]
Common Shares Issued	554
Common Share Value	23.8
Cash Paid	0
Accrued Liability	0
Escrow Deposited	2.7
Recorded Earnout Payable	6.4
Total Recorded Purchase Price	32.9
Maximum Potential Earnout Payable	12.5
Independent Benefit Services, Inc. (IBS) [Member]
Business Acquisition [Line Items]
Common Shares Issued	395
Common Share Value	17.8
Cash Paid	6.2
Accrued Liability	0
Escrow Deposited	0.8
Recorded Earnout Payable	1.3
Total Recorded Purchase Price	26.1
Maximum Potential Earnout Payable	14.3
Affinity Marketing Group [Member]
Business Acquisition [Line Items]
Common Shares Issued	72
Common Share Value	3.1
Cash Paid	0
Accrued Liability	0
Escrow Deposited	0.3
Recorded Earnout Payable	2.2
Total Recorded Purchase Price	5.6
Maximum Potential Earnout Payable	5.2
Blue Holdings Group of Companies [Member]
Business Acquisition [Line Items]
Common Shares Issued	227
Common Share Value	10.9
Cash Paid	4.5
Accrued Liability	0
Escrow Deposited	1.7
Recorded Earnout Payable	1.2
Total Recorded Purchase Price	18.3
Maximum Potential Earnout Payable	6.6
Twenty One Other Acquisitions [Member]
Business Acquisition [Line Items]
Common Shares Issued	344
Common Share Value	14.8
Cash Paid	18.5
Accrued Liability	0
Escrow Deposited	1.1
Recorded Earnout Payable	10.3
Total Recorded Purchase Price	44.7
Maximum Potential Earnout Payable	$21.10

Business_Combinations_Acquisit1

Business Combinations - Acquisition Method for Recording Business Combinations (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2014
Benefit Development Group, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Feb-14
Kent, Kent & Tingle [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Feb-14
L&R Benefits, LLC [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Mar-14
Spataro Insurance Agency, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Mar-14
Tudor Risk Services, LLC [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Mar-14
American Wholesalers Underwriting Ltd [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Apr-14
Mike Henry Insurance Brokers Limited [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Apr-14
Oval Group of Companies (OGC) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Apr-14
Heritage Insurance Management Limited (HIM) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-May-14
MGA Insurance Group (MGA) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-May-14
Shilling Limited [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-May-14
Sunderland Insurance Services, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-May-14
Plus Companies, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Jun-14
Tri-State General Insurance Agency, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Jun-14
Crombie/OAMPS (CO) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	16-Jun-14
Foundation Strategies, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Jul-14
Insurance Point, LLC (IPL) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Jul-14
Trip Mate, Inc. (TMI) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Jul-14
Noraxis Capital Corporation (NCC) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	2-Jul-14
Cowles & Connell (CC) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Aug-14
Denman Consulting Services [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Aug-14
Minvielle & Chastanet Insurance Brokers [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	8-Aug-14
Baker Tilly Financial Management Limited [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	29-Aug-14
Benfield Group [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Sep-14
Everett James, Inc. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Sep-14
Hagedorn & Company [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Sep-14
Parmia Pty Ltd. [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Sep-14
Bennett and Shade Company [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Oct-14
Insurance Associates Inc [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Oct-14
Forker Company [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	31-Oct-14
Discovery Benefit Solutions Inc [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Nov-14
Miller Harrison Insurance Services [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Nov-14
SGB-NIA Insurance Brokers (SGB) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Nov-14
Titan Group LLC [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Nov-14
Instrat Insurance Brokers [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Dec-14
O Gorman & Young Incorporated (OGY) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Dec-14
Independent Benefit Services, Inc. (IBS) [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Dec-14
Affinity Marketing Group [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	1-Dec-14
Blue Holdings Group of Companies [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition	5-Dec-14

Business_Combinations_Addition

Business Combinations - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			156 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Apr. 16, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Oct. 14, 2014	Sep. 30, 2014
	Apr. 16, 2014	Entity	Entity	Entity	Entity	Oct. 14, 2014	Sep. 30, 2014
Business Acquisition [Line Items]
Cash paid for acquisition of equity interest		$1,914.50
Common stock issued for net proceeds	21.85
Net proceeds from common stock issued	911.4	911.4
Accretion of the discount on acquisition		14.5	11.9	9.3
Income related to net adjustments to estimated fair value of liability for earnout obligations		3	10.2	5.9
Number of companies acquired		67	79	46	339
Aggregate amount of maximum earnout obligations related to acquisitions		549.8	462.3
Aggregate amount of maximum earnout obligations related to acquisitions, recorded in consolidated balance sheet		205.3	162.7
Goodwill		1,448.30			1,448.30
Expiration lists		895.9			895.9
Non-compete agreements		11.9			11.9
Trade name		9.4			9.4
Total revenues related to acquisitions in the aggregate		4,984.20	3,968.10
Net earnings		316.1	298.4
Brokerage [Member]
Business Acquisition [Line Items]
Goodwill							1,448.30
Expiration lists							895.9
Non-compete agreements							11.9
Trade name							9.4
Oval Group of Companies (OGC) [Member]
Business Acquisition [Line Items]
Cash paid for acquisition of equity interest		338.4
Acquisition agreement date		1-Apr-14
Number of employees at offices of acquired entity		1,000
Number of offices in which acquiree entity operates		24
Goodwill		245.7			245.7
Expiration lists		129.9			129.9
Non-compete agreements		1			1
Trade name		0.6			0.6
Noraxis Capital Corporation (NCC) [Member]
Business Acquisition [Line Items]
Cash paid for acquisition of equity interest		413.3
Acquisition agreement date		2-Jul-14
Number of employees at offices of acquired entity		650
Percentage of equity on which cash consideration paid		89.00%			89.00%
Goodwill		314.9			314.9
Expiration lists		178.6			178.6
Non-compete agreements		2.6			2.6
Trade name		2.2			2.2
2013 Acquisitions [Member] \| Income Approach Valuation Technique [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Revenue growth rate		2.00%
Discount rate		10.50%
Attrition rate		5.00%
2013 Acquisitions [Member] \| Income Approach Valuation Technique [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Revenue growth rate		3.00%
Discount rate		15.00%
Attrition rate		11.50%
Business Acquisition [Member]
Business Acquisition [Line Items]
Annualized revenue of business acquisitions		761.2
Total revenues related to acquisitions in the aggregate		413
Net earnings		37.8
Business Acquisition [Member] \| Brokerage [Member]
Business Acquisition [Line Items]
Expiration lists		895.9			895.9
Non-compete agreements		11.9			11.9
Trade name		9.4			9.4
Deferred tax liability		173.9			173.9
Goodwill related to nondeductible amortizable intangible assets		173.9
Business Acquisition [Member] \| Brokerage [Member] \| Expiration Lists [Member]
Business Acquisition [Line Items]
Business acquisition not deductible for income tax purposes		679.3			679.3
Business Acquisition [Member] \| Brokerage [Member] \| Non-Compete Agreements [Member]
Business Acquisition [Line Items]
Business acquisition not deductible for income tax purposes		9.9			9.9
Business Acquisition [Member] \| Brokerage [Member] \| Trade Names [Member]
Business Acquisition [Line Items]
Business acquisition not deductible for income tax purposes		7.1			7.1
Crombie Lockwood Oamps [Member]
Business Acquisition [Line Items]
Cash paid for acquisition of equity interest		952
Acquisition agreement date		16-Jun-14
Number of employees at offices of acquired entity		1,700
Number of offices in which acquiree entity operates		50
Payment for excess of net current assets						$35.30
2014 Acquisitions [Member] \| Market Approach Valuation Technique [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Revenue growth rate		4.00%
Discount rate		8.50%
2014 Acquisitions [Member] \| Market Approach Valuation Technique [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Revenue growth rate		12.00%
Discount rate		9.50%

Business_Combinations_Summary_

Business Combinations - Summary of Estimated Fair Values of Net Assets Acquired (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	$68.70
Other current assets	975.1
Fixed assets	29.8
Noncurrent assets	15.5
Goodwill	1,448.30
Expiration lists	895.9
Non-compete agreements	11.9
Trade names	9.4
Total assets acquired	3,454.60
Current liabilities	771.1
Noncurrent liabilities	394
Total liabilities assumed	1,165.10
Total net assets acquired	2,289.50
Oval Group of Companies (OGC) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	23.1
Other current assets	129.6
Fixed assets	2.1
Noncurrent assets	0
Goodwill	245.7
Expiration lists	129.9
Non-compete agreements	1
Trade names	0.6
Total assets acquired	532
Current liabilities	129.5
Noncurrent liabilities	52.3
Total liabilities assumed	181.8
Total net assets acquired	350.2
Heritage Insurance Management Limited (HIM) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	2.9
Other current assets	4.9
Fixed assets	0.3
Noncurrent assets	0
Goodwill	14.8
Expiration lists	20.3
Non-compete agreements	1.3
Trade names	0
Total assets acquired	44.5
Current liabilities	6.8
Noncurrent liabilities	0
Total liabilities assumed	6.8
Total net assets acquired	37.7
MGA Insurance Group (MGA) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	0.2
Other current assets	8.9
Fixed assets	0.8
Noncurrent assets	0
Goodwill	27
Expiration lists	33.2
Non-compete agreements	0.3
Trade names	0
Total assets acquired	70.4
Current liabilities	4.1
Noncurrent liabilities	0
Total liabilities assumed	4.1
Total net assets acquired	66.3
Crombie/OAMPS (CO) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	26.6
Other current assets	695.5
Fixed assets	17.1
Noncurrent assets	7
Goodwill	619.6
Expiration lists	325.3
Non-compete agreements	4.2
Trade names	4.2
Total assets acquired	1,699.50
Current liabilities	490
Noncurrent liabilities	216.4
Total liabilities assumed	706.4
Total net assets acquired	993.1
Noraxis Capital Corporation (NCC) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	10.1
Other current assets	73
Fixed assets	4.9
Noncurrent assets	3.5
Goodwill	314.9
Expiration lists	178.6
Non-compete agreements	2.6
Trade names	2.2
Total assets acquired	589.8
Current liabilities	72.5
Noncurrent liabilities	102.1
Total liabilities assumed	174.6
Total net assets acquired	415.2
SGB-NIA Insurance Brokers (SGB) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	0
Other current assets	0.7
Fixed assets	0.1
Noncurrent assets	0.1
Goodwill	14.9
Expiration lists	17.8
Non-compete agreements	0.1
Trade names	0
Total assets acquired	33.7
Current liabilities	0.7
Noncurrent liabilities	0
Total liabilities assumed	0.7
Total net assets acquired	33
O Gorman & Young Incorporated (OGY) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	0
Other current assets	2.8
Fixed assets	0.2
Noncurrent assets	0
Goodwill	25.8
Expiration lists	18.7
Non-compete agreements	0.3
Trade names	0
Total assets acquired	47.8
Current liabilities	4.1
Noncurrent liabilities	10.8
Total liabilities assumed	14.9
Total net assets acquired	32.9
Independent Benefit Services, Inc. (IBS) [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	0
Other current assets	0.5
Fixed assets	0
Noncurrent assets	0
Goodwill	12.7
Expiration lists	13.1
Non-compete agreements	0.2
Trade names	0
Total assets acquired	26.5
Current liabilities	0.4
Noncurrent liabilities	0
Total liabilities assumed	0.4
Total net assets acquired	26.1
Fifty-Two Other Acquisitions [Member]
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Cash	5.8
Other current assets	59.2
Fixed assets	4.3
Noncurrent assets	4.9
Goodwill	172.9
Expiration lists	159
Non-compete agreements	1.9
Trade names	2.4
Total assets acquired	410.4
Current liabilities	63
Noncurrent liabilities	12.4
Total liabilities assumed	75.4
Total net assets acquired	$335

Business_Combinations_Summary_1

Business Combinations - Summary of Unaudited Pro Forma Historical Results (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Business Combinations [Abstract]
Total revenues	$4,984.20	$3,968.10
Net earnings	$316.10	$298.40
Basic earnings per share	$1.94	$1.91
Diluted earnings per share	$1.93	$1.89

Other_Current_Assets_Summary_o

Other Current Assets - Summary of Major Classes of Other Current Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Premium finance advances and loans	$232.60	$2.30
Accrued supplemental, direct bill and other receivables	156.3	69
Refined coal production related receivables	103.5	56.6
Deferred income taxes - current	102.2	84.9
Prepaid expenses	72.1	48.5
Total other current assets	$666.70	$261.30

Other_Current_Assets_Additiona

Other Current Assets - Additional Information (Detail)	12 Months Ended
Other Current Assets - Additional Information (Detail)	Dec. 31, 2014
Schedule Of Other Current Assets [Line Items]
Collateralized delinquency period of receivables	7 days
Crombie Lockwood Oamps [Member]
Schedule Of Other Current Assets [Line Items]
Acquisition agreement date	16-Jun-14

Fixed_Assets_Summery_of_Fixed_

Fixed Assets - Summery of Fixed Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property Plant and Equipment Useful Life and Values [Abstract]
Office equipment	$23	$16.30
Furniture and fixtures	89.6	78.3
Computer equipment	133.9	117.2
Leasehold improvements	102.9	77.9
Software	187.8	147.6
Other	11.5	8.5
Gross fixed assets	548.7	445.8
Accumulated depreciation	-353.3	-285.4
Net fixed assets	$195.40	$160.40

Intangible_Assets_Carrying_Amo

Intangible Assets - Carrying Amount of Goodwill Allocated by Domestic and Foreign Operations (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Total goodwill - net	$3,449.60	$2,145.20	$1,472.70
Unites States [Member]
Goodwill [Line Items]
Total goodwill - net	1,672.80	1,469.80
United Kingdom [Member]
Goodwill [Line Items]
Total goodwill - net	820.6	584.9
Canada [Member]
Goodwill [Line Items]
Total goodwill - net	318.5	26.8
Australia [Member]
Goodwill [Line Items]
Total goodwill - net	336.8	37.1
Other Foreign, Principally New Zealand [Member]
Goodwill [Line Items]
Total goodwill - net	300.9	26.6
Brokerage [Member]
Goodwill [Line Items]
Total goodwill - net	3,427.50	2,122.90	1,451.40
Brokerage [Member] \| Unites States [Member]
Goodwill [Line Items]
Total goodwill - net	1,652.60	1,449.60
Brokerage [Member] \| United Kingdom [Member]
Goodwill [Line Items]
Total goodwill - net	818.7	582.8
Brokerage [Member] \| Canada [Member]
Goodwill [Line Items]
Total goodwill - net	318.5	26.8
Brokerage [Member] \| Australia [Member]
Goodwill [Line Items]
Total goodwill - net	336.8	37.1
Brokerage [Member] \| Other Foreign, Principally New Zealand [Member]
Goodwill [Line Items]
Total goodwill - net	300.9	26.6
Risk Management [Member]
Goodwill [Line Items]
Total goodwill - net	22.1	22.3	21.3
Risk Management [Member] \| Unites States [Member]
Goodwill [Line Items]
Total goodwill - net	20.2	20.2
Risk Management [Member] \| United Kingdom [Member]
Goodwill [Line Items]
Total goodwill - net	1.9	2.1
Risk Management [Member] \| Canada [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Risk Management [Member] \| Australia [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Risk Management [Member] \| Other Foreign, Principally New Zealand [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Corporate [Member]
Goodwill [Line Items]
Total goodwill - net	0	0	0
Corporate [Member] \| Unites States [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Corporate [Member] \| United Kingdom [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Corporate [Member] \| Canada [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Corporate [Member] \| Australia [Member]
Goodwill [Line Items]
Total goodwill - net	0	0
Corporate [Member] \| Other Foreign, Principally New Zealand [Member]
Goodwill [Line Items]
Total goodwill - net	$0	$0

Intangible_Assets_Changes_in_C

Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Beginning Balance	$2,145.20	$1,472.70
Goodwill acquired during the year	1,448.30	665
Goodwill adjustments related to appraisals and other acquisition adjustments	-8.8	3.3
Goodwill written-off related to sales of business	-0.6
Foreign currency translation adjustments during the year	-134.5	4.2
Ending Balance	3,449.60	2,145.20
Brokerage [Member]
Goodwill [Line Items]
Beginning Balance	2,122.90	1,451.40
Goodwill acquired during the year	1,448.30	664.1
Goodwill adjustments related to appraisals and other acquisition adjustments	-8.8	3.3
Goodwill written-off related to sales of business	-0.6
Foreign currency translation adjustments during the year	-134.3	4.1
Ending Balance	3,427.50	2,122.90
Risk Management [Member]
Goodwill [Line Items]
Beginning Balance	22.3	21.3
Goodwill acquired during the year	0	0.9
Goodwill adjustments related to appraisals and other acquisition adjustments	0	0
Goodwill written-off related to sales of business	0
Foreign currency translation adjustments during the year	-0.2	0.1
Ending Balance	22.1	22.3
Corporate [Member]
Goodwill [Line Items]
Beginning Balance	0	0
Goodwill acquired during the year	0	0
Goodwill adjustments related to appraisals and other acquisition adjustments	0	0
Goodwill written-off related to sales of business	0
Foreign currency translation adjustments during the year	0	0
Ending Balance	$0	$0

Intangible_Assets_Major_Classe

Intangible Assets - Major Classes of Amortizable Intangible Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, net	$1,776	$1,078.80	$809.60
Expiration Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	2,461.90	1,563.50
Accumulated amortization	-719.3	-511.3
Amortizable intangible assets, net	1,742.60	1,052.20
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	43.2	37.3
Accumulated amortization	-29.5	-25.9
Amortizable intangible assets, net	13.7	11.4
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	29.7	22.1
Accumulated amortization	-10	-6.9
Amortizable intangible assets, net	$19.70	$15.20

Intangible_Assets_Estimated_Ag

Intangible Assets - Estimated Aggregate Amortization Expense (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$214.60
2016	208.5
2017	198.7
2018	187.2
2019	173.6
Total	$982.60

Credit_and_Other_Debt_Agreemen2

Credit and Other Debt Agreements - Summary of Corporate and Other Debt (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Semi-annual payments of interest	$2,392.90	$1,455.50
Premium Financing Debt Facility [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	127.9
Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	2,125	925
Fixed Rate of 6.26%, Balloon Due 2014 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest		100
Fixed Rate of 6.44%, Balloon Due 2017 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	300	300
Fixed Rate of 2.80%, Balloon Due 2018 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	50
Fixed Rate of 3.20%, Balloon Due 2019 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	50
Fixed Rate of 5.85%, $50.0 Million Due in 2016, 2018 and 2019 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	150	150
Fixed Rate of 3.99%, Balloon Due 2020 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	50	50
Fixed Rate of 3.48%, Balloon Due 2020 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	50
Fixed Rate of 5.18%, Balloon Due 2021 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	75	75
Fixed rate of 3.69%, Balloon Due 2022 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	200	200
Fixed Rate of 5.49%, Balloon Due 2023 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	50	50
Fixed Rate of 4.13%, Balloon Due 2023 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	200
Fixed Rate of 4.58% Balloon Due 2024 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	325
Fixed Rate of 4.31%, Balloon Due 2025 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	200
Fixed Rate of 4.73% Balloon Due 2026 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	175
Fixed Rate of 4.36%, Balloon Due 2026 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	150
Fixed Rate of 4.98% Balloon Due 2029 [Member] \| Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	100
Prime or LIBOR plus up to 1.45%, expires September 19, 2018 [Member] \| Multi Currency Credit Agreement [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	140	530.5
Interbank rates plus 1.65%, Expires June 15, 2016 [Member] \| AUD denominated tranche [Member] \| Facility B [Member] \| Premium Financing Debt Facility [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	95
Interbank rates plus 1.65%, Expires June 15, 2016 [Member] \| NZD denominated tranche [Member] \| Facility B [Member] \| Premium Financing Debt Facility [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	17.8
Interbank rates plus 0.85%, Expires June 15, 2016 [Member] \| AUD denominated tranche [Member] \| Facility C and D [Member] \| Premium Financing Debt Facility [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	7.7
Interbank rates plus 0.85%, Expires June 15, 2016 [Member] \| NZD denominated tranche [Member] \| Facility C and D [Member] \| Premium Financing Debt Facility [Member]
Debt Instrument [Line Items]
Semi-annual payments of interest	$7.40

Credit_and_Other_Debt_Agreemen3

Credit and Other Debt Agreements - Summary of Corporate and Other Debt (Parenthetical) (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fixed Rate of 6.26%, Balloon Due 2014 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	6.26%	6.26%
Principal payments, year due	2014	2014
Fixed Rate of 6.44%, Balloon Due 2017 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	6.44%	6.44%
Principal payments, year due	2017	2017
Fixed Rate of 2.80%, Balloon Due 2018 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	2.80%	2.80%
Principal payments, year due	2018	2018
Fixed Rate of 3.20%, Balloon Due 2019 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	3.20%	3.20%
Principal payments, year due	2019	2019
Fixed Rate of 5.85%, $50.0 Million Due in 2016, 2018 and 2019 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	5.85%	5.85%
Long-Term debt maturities repayments in 2016	50	50
Long-Term debt maturities repayments in 2018	50	50
Long-Term debt maturities repayments in 2019	50	50
Fixed Rate of 5.85%, $50.0 Million Due in 2016, 2018 and 2019 [Member] \| First Installment [Member]
Debt Instrument [Line Items]
Principal payments, year due	2016	2016
Fixed Rate of 5.85%, $50.0 Million Due in 2016, 2018 and 2019 [Member] \| Second Installment [Member]
Debt Instrument [Line Items]
Principal payments, year due	2018	2018
Fixed Rate of 5.85%, $50.0 Million Due in 2016, 2018 and 2019 [Member] \| Third Installment [Member]
Debt Instrument [Line Items]
Principal payments, year due	2019	2019
Fixed Rate of 3.99%, Balloon Due 2020 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	3.99%	3.99%
Principal payments, year due	2020	2020
Fixed Rate of 3.48%, Balloon Due 2020 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	3.48%	3.48%
Principal payments, year due	2020	2020
Fixed Rate of 5.18%, Balloon Due 2021 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	5.18%	5.18%
Principal payments, year due	2021	2021
Fixed rate of 3.69%, Balloon Due 2022 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	3.69%	3.69%
Principal payments, year due	2022	2022
Fixed Rate of 5.49%, Balloon Due 2023 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	5.49%	5.49%
Principal payments, year due	2023	2023
Fixed Rate of 4.13%, Balloon Due 2023 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	4.13%	4.13%
Principal payments, year due	2023	2023
Fixed Rate of 4.58% Balloon Due 2024 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	4.58%	4.58%
Principal payments, year due	2024	2024
Fixed Rate of 4.31%, Balloon Due 2025 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	4.31%	4.31%
Principal payments, year due	2025	2025
Fixed Rate of 4.73% Balloon Due 2026 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	4.73%	4.73%
Principal payments, year due	2026	2026
Fixed Rate of 4.36%, Balloon Due 2026 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	4.36%	4.36%
Principal payments, year due	2026	2026
Fixed Rate of 4.98% Balloon Due 2029 [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	4.98%	4.98%
Principal payments, year due	2029	2029
Prime or LIBOR plus up to 1.45%, expires September 19, 2018 [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	1.45%	1.45%
Periodic payments of interest and principal, expiry date	19-Sep-18	19-Sep-18
Premium Financing Debt Facility [Member]
Debt Instrument [Line Items]
Periodic payments of interest and principal, expiry date	15-Jun-16	15-Jun-16
Premium Financing Debt Facility [Member] \| Interbank rates plus 1.65%, Expires June 15, 2016 [Member] \| Facility B [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	1.65%	1.65%
Premium Financing Debt Facility [Member] \| Interbank rates plus 0.85%, Expires June 15, 2016 [Member] \| Facility C and D [Member]
Debt Instrument [Line Items]
Periodic Payment of Interest	0.85%	0.85%

Credit_and_Other_Debt_Agreemen4

Credit and Other Debt Agreements - Note Purchase Agreements - Additional information (Detail) (Note Purchase Agreements [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Debt Instrument [Line Items]
Amount payable to redeem the notes, percent of the principal amount	100.00%
Discount rate used to compute the remaining scheduled payments of principal and interest	U.S. Treasury yields plus 0.5%
6.44% Senior Notes, Series B [Member]
Debt Instrument [Line Items]
Notes issued and sold	300
Note payable, semi-annual payments of interest, fixed rate	6.44%
Debt instrument, maturity date	3-Aug-17
5.85% Senior Notes, Series C [Member]
Debt Instrument [Line Items]
Notes issued and sold	150
Note payable, semi-annual payments of interest, fixed rate	5.85%
5.85% Senior Notes, Series C [Member] \| First Installment [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	30-Nov-16
5.85% Senior Notes, Series C [Member] \| Second Installment [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	30-Nov-18
5.85% Senior Notes, Series C [Member] \| Third Installment [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	30-Nov-19
5.18% Senior Notes, Series D [Member]
Debt Instrument [Line Items]
Notes issued and sold	75
Note payable, semi-annual payments of interest, fixed rate	5.18%
Debt instrument, maturity date	10-Feb-21
5.49% Senior Notes, Series E [Member]
Debt Instrument [Line Items]
Notes issued and sold	50
Note payable, semi-annual payments of interest, fixed rate	5.49%
Debt instrument, maturity date	10-Feb-23
3.99% Senior Notes, Series F [Member]
Debt Instrument [Line Items]
Notes issued and sold	50
Note payable, semi-annual payments of interest, fixed rate	3.99%
Debt instrument, maturity date	10-Jul-20
3.69% Senior Notes Series G [Member] \| Private Placement [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	14-Jun-22
Private placement debt, additional amount committed to borrow	200
Interest rate	3.69%
4.58% Senior Notes, Series H [Member]
Debt Instrument [Line Items]
Notes issued and sold	325
Note payable, semi-annual payments of interest, fixed rate	4.58%
Debt instrument, maturity date	27-Feb-24
4.73% Senior Notes, Series I [Member]
Debt Instrument [Line Items]
Notes issued and sold	175
Note payable, semi-annual payments of interest, fixed rate	4.73%
Debt instrument, maturity date	27-Feb-26
4.98% Senior Notes, Series J [Member]
Debt Instrument [Line Items]
Notes issued and sold	100
Note payable, semi-annual payments of interest, fixed rate	4.98%
Debt instrument, maturity date	27-Feb-29
Senior Notes Series H, I & J [Member]
Debt Instrument [Line Items]
Debt acquisition costs	1.4
2.80% Senior Notes, Series K [Member]
Debt Instrument [Line Items]
Notes issued and sold	50
Note payable, semi-annual payments of interest, fixed rate	2.80%
Debt instrument, maturity date	24-Jun-18
3.20% Senior Notes, Series L [Member]
Debt Instrument [Line Items]
Notes issued and sold	50
Note payable, semi-annual payments of interest, fixed rate	3.20%
Debt instrument, maturity date	24-Jun-19
3.48% Senior Notes, Series M [Member]
Debt Instrument [Line Items]
Notes issued and sold	50
Note payable, semi-annual payments of interest, fixed rate	3.48%
Debt instrument, maturity date	24-Jun-20
4.13% Senior Notes, Series N [Member]
Debt Instrument [Line Items]
Notes issued and sold	200
Note payable, semi-annual payments of interest, fixed rate	4.13%
Debt instrument, maturity date	24-Jun-23
4.31% Senior Notes, Series O [Member]
Debt Instrument [Line Items]
Notes issued and sold	200
Note payable, semi-annual payments of interest, fixed rate	4.31%
Debt instrument, maturity date	24-Jun-25
4.36% Senior Notes, Series P [Member]
Debt Instrument [Line Items]
Notes issued and sold	150
Note payable, semi-annual payments of interest, fixed rate	4.36%
Debt instrument, maturity date	24-Jun-26
Senior Notes Series K, L, M, N, O & P [Member]
Debt Instrument [Line Items]
Debt acquisition costs	2.6

Credit_and_Other_Debt_Agreemen5

Credit and Other Debt Agreements - Credit Agreement - Additional information (Detail)

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

USD ($)

Revolving Credit Facility [Member]

Multi Currency Credit Agreement [Member]

Credit Facility Two [Member]

Credit Facility Three [Member]

Credit Facility Four [Member]

Note Purchase Agreements [Member]

USD ($)

Swing Loan [Member]

Standby Letters of Credit [Member]

Revolving Credit Facility [Member]

Level 3 [Member]

Institution

USD ($)

AUD

NZD

AUD

NZD

AUD

USD ($)

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$600,000,000

Number of financial institutions entered in unsecured multicurrency credit agreement

Debt instrument, maturity date

19-Sep-18

Long-term debt, gross

50,000,000

75,000,000

Line of credit facility, maximum amount outstanding during period

850,000,000

Fixed rate (alternative one) over LIBOR

0.85%

Fixed rate (alternative two) over LIBOR

0.95%

Fixed rate (alternative three) over LIBOR

1.05%

Fixed rate (alternative four) over LIBOR

1.25%

Fixed rate (alternative five) over LIBOR

1.45%

Annual facility fee of revolving credit facility (alternative one)

0.15%

Annual facility fee of revolving credit facility (alternative two)

0.18%

Annual facility fee of revolving credit facility (alternative three)

0.20%

Annual facility fee of revolving credit facility (alternative four)

0.25%

Annual facility fee of revolving credit facility (alternative five)

0.30%

Debt acquisition costs

2,100,000

Line of credit facility, amount outstanding

22,600,000

117,000,000

23,000,000

9,400,000

9,600,000

Liabilities

6,780,600,000

4,775,000,000

9,700,000

Line of credit facility, fair value of amount outstanding

140,000,000

2,281,000,000

Line of credit facility, remaining borrowing capacity

437,400,000

33,000,000

12,000,000

15,600,000

5,400,000

15,600,000

Line of credit facility, increase in additional borrowings

1,109,900,000

890,500,000

303,000,000

52,400,000

Net borrowings on premium financing debt facility

7,500,000

150,000,000

35,000,000

25,000,000

15,000,000

Date of expire

15-Jun-16

Interest rate for facility

The interest rates on Facility B are Interbank rates, which vary by tranche, duration and currency, plus a margin of 1.65%. The interest rates on Facilities C and D are 30 day Interbank rates, plus a margin of 0.85%.B The annual fee for Facility B is 0.7425% of the undrawn commitments for the two tranches of the facility.B The annual fee for Facilities C and D is 0.80% of the total commitments of the facilities.B In connection with entering into the Premium Financing Debt Facility, we incurred an upfront fee of 0.30% of the principal amount of the committed facilities.

Additional margin percentage on interest rate

1.65%

0.85%

Annual fee percentage

0.74%

0.80%

Up front fee percentage for entering into premium financing debt facility

0.30%

Long-term debt

46,100,000

2,125,000,000

Estimated fair value of outstanding borrowings

140,000,000

Debt instrument fair value amount

$127,900,000

Earnings_Per_Share_Computation

Earnings Per Share - Computation of Basic and Diluted Net EPS (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net earnings	$51.50	$93.60	$109	$49.30	$60	$74.60	$93.50	$40.50	$303.40	$268.60	$195
Weighted average number of common shares outstanding									152.9	128.9	121
Dilutive effect of stock options using the treasury stock method									1.4	1.6	1.5
Weighted average number of common and common equivalent shares outstanding									154.3	130.5	122.5
Basic net earnings per share									$1.98	$2.08	$1.61
Diluted net earnings per share									$1.97	$2.06	$1.59

Earnings_Per_Share_Additional_

Earnings Per Share - Additional information (Detail)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Options to purchase common stock shares outstanding	1.6	1.3	1.1

Stock_Option_Plans_Additional_

Stock Option Plans - Additional information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 12, 2014	Mar. 13, 2013	Mar. 16, 2012
Stock Option Plans [Line Items]
Maximum number of shares available	376,541	369,975	361,400
Maximum number of shares granted during any fiscal year to any person	200,000
Maximum period for the exercise of stock options, years	7 years
Minimum exercise price of stock options, percent of fair market value of a share of common stock on the date of grant	100.00%
Number of years options expire, maximum	7 years	7 years	7 years
Compensation expense related to stock option grants	$9,500,000	$7,700,000	$7,200,000
Total intrinsic value of options exercised	30,500,000	32,000,000	26,000,000
Total unrecognized compensation cost related to nonvested options	28,800,000
Weighted average period, years	4 years
Minimum [Member]
Stock Option Plans [Line Items]
Period of Service from Grant Date Stock Options Awarded Not Subject to Forfeiture	2 years
Officer and Key Employees [Member]
Stock Option Plans [Line Items]
Shares available for grant				1,923,000	1,665,000	1,355,000
Stock options granted, exercise percentage, on the anniversary date of the grant in 2017				34.00%	34.00%	34.00%
Stock options granted, exercise percentage, on the anniversary date of the grant in 2018				33.00%	33.00%	33.00%
Stock options granted, exercise percentage, on the anniversary date of the grant in 2019				33.00%	33.00%	33.00%
Executive Officer [Member]
Stock Option Plans [Line Items]
Minimum age of employee with not subject to award forfeiture on condition compliance	55 years
Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Maximum number of shares available	2,000,000
Shares available for grant	9,300,000
Performance-Based Restricted Stock [Member]
Stock Option Plans [Line Items]
Maximum number of shares granted during any fiscal year to any person	100,000
Incentive Plan Prior to 2007 [Member]
Stock Option Plans [Line Items]
Stock options granted, exercise rate per year	10.00%
Non Qualified Plan Prior to 2007 [Member] \| Officer and Key Employees [Member]
Stock Option Plans [Line Items]
Stock options granted, exercise rate per year	10.00%
Accelerated vesting in the event of death, disability or retirement	100.00%
Prior to 2009 Options [Member]
Stock Option Plans [Line Items]
Number of years options expire, maximum	10 years
Cash Settled Performance Shares [Member] \| Performance-Based Restricted Stock [Member]
Stock Option Plans [Line Items]
Maximum amount payable for the shares granted during any fiscal year to any person	$5,000,000
Stock Settled Performance Shares [Member] \| Performance-Based Restricted Stock [Member]
Stock Option Plans [Line Items]
Maximum number of shares granted during any fiscal year to any person	100,000
Black-Scholes Option Pricing Model [Member]
Stock Option Plans [Line Items]
Weighted average fair value per option for all options	$9.66	$7.51	$5.49

Stock_Option_Plans_BlackSchole

Stock Option Plans - Black-Scholes Option Pricing Model with Weighted Average (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected dividend yield	3.00%	3.50%	4.00%
Expected risk-free interest rate	1.80%	1.20%	1.20%
Volatility	28.90%	29.60%	26.90%
Expected life (in years)	5 years 6 months	6 years	5 years

Stock_Option_Plans_Stock_Optio

Stock Option Plans - Stock Option Activity and Related Information (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares Under Option, Beginning balance	8.3	9	10.6
Shares Under Option, Granted	1.9	1.7	1.4
Shares Under Option, Exercised	-1.7	-2.3	-2.8
Shares Under Option, Forfeited or canceled	-0.1	-0.1	-0.2
Shares Under Option, Ending balance	8.4	8.3	9
Shares Under Option, Exercisable at end of period	2.6	3.8	5.1
Shares Under Option, Ending vested and expected to vest	8.3	8.2	8.9
Weighted Average Exercise Price, Beginning balance	$31.35	$28.80	$27.20
Weighted Average Exercise Price, Granted	$46.86	$39.17	$35.71
Weighted Average Exercise Price, Exercised	$28.80	$27.11	$26.14
Weighted Average Exercise Price, Forfeited or canceled	$28.36	$26.01	$29.46
Weighted Average Exercised Price, Ending balance	$35.49	$31.35	$28.80
Weighted Average Exercise Price, Exercisable at end of period	$26.91	$27.64	$27.50
Weighted Average Exercise price, Ending vested and expected to vest	$35.38	$31.28	$28.76
Weighted Average Remaining Contractual Term (in years), Ending balance	3 years 11 months 16 days	3 years 7 months 13 days	3 years 4 months 28 days
Weighted Average Remaining Contractual Term (in years), Exercisable at end of period	1 year 10 months 13 days	2 years 1 month 24 days	2 years 6 months 7 days
Weighted Average Remaining Contractual Term (in years), Ending vested and expected to vested	3 years 11 months 5 days	3 years 7 months 2 days	3 years 4 months 21 days
Aggregate Intrinsic Value, Ending Balance	$97.20	$129.40	$53.90
Aggregate Intrinsic Value, Exercisable at end of period	52.8	72.5	36.3
Aggregate Intrinsic Value, Ending vested and expected to vest	$96.60	$128.30	$53.80

Stock_Option_Plans_Stock_Optio1

Stock Option Plans - Stock Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$21.28
Range of Exercise Prices, maximum	$46.87
Option Outstanding, Number Outstanding	8.4
Option Outstanding, Weighted Average Remaining Contractual Term (in years)	3 years 11 months 16 days	3 years 7 months 13 days	3 years 4 months 28 days
Option Outstanding, Weighted Average Exercise Price	$35.49	$31.35	$28.80	$27.20
Options Exercisable, Number Exercisable	2.6
Option Exercisable, Weighted Average Exercise Price	$26.91
Exercise Prices Range $ 21.28 - $ 27.25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$21.28
Range of Exercise Prices, maximum	$27.25
Option Outstanding, Number Outstanding	2.3
Option Outstanding, Weighted Average Remaining Contractual Term (in years)	1 year 7 months 2 days
Option Outstanding, Weighted Average Exercise Price	$25.78
Options Exercisable, Number Exercisable	1.9
Option Exercisable, Weighted Average Exercise Price	$25.76
Exercise Prices Range $ 27.35 - $ 35.71 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$27.35
Range of Exercise Prices, maximum	$35.71
Option Outstanding, Number Outstanding	2.5
Option Outstanding, Weighted Average Remaining Contractual Term (in years)	3 years 7 months 2 days
Option Outstanding, Weighted Average Exercise Price	$33.18
Options Exercisable, Number Exercisable	0.7
Option Exercisable, Weighted Average Exercise Price	$29.83
Exercise Prices Range $ 35.95 - $ 39.17 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$35.95
Range of Exercise Prices, maximum	$46.16
Option Outstanding, Number Outstanding	1.7
Option Outstanding, Weighted Average Remaining Contractual Term (in years)	5 years 2 months 12 days
Option Outstanding, Weighted Average Exercise Price	$39.19
Options Exercisable, Number Exercisable	0
Option Exercisable, Weighted Average Exercise Price	$0
Exercise Prices Range $ 46.16 - $ 46.16 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$46.87
Range of Exercise Prices, maximum	$46.87
Option Outstanding, Number Outstanding	1.9
Option Outstanding, Weighted Average Remaining Contractual Term (in years)	6 years 2 months 9 days
Option Outstanding, Weighted Average Exercise Price	$46.87
Options Exercisable, Number Exercisable	0
Option Exercisable, Weighted Average Exercise Price	$0

Deferred_Compensation_Addition

Deferred Compensation - Additional information (Detail) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investments And Employee Deferred Compensation Plan [Line Items]
Deferred Equity Participation Plan, distributions to key executives, age					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
Age 62 Plan [Member]
Investments And Employee Deferred Compensation Plan [Line Items]
Awards approved by committee, value	$9.20		$8	$7.30
Charge to compensation expenses related to awards					7.4	7.2	5.4
Common stock Purchased from open Market, Share		1.2
Common stock Purchased from open Market, Value		52.4
Unearned deferred compensation, value					28.2	26.3
Unearned deferred compensation, shares					1.9	2.1
Total intrinsic value of unvested equity based awards					89.1	96.4
Cash and equity awards with aggregate fair value vested and distributed to participants					18.8	1.4	0.7
Deferred Cash Participation Plan (DCPP) [Member]
Investments And Employee Deferred Compensation Plan [Line Items]
Awards approved by committee, value	2.9		2.7
Charge to compensation expenses related to awards					2.8
Cash and equity awards with aggregate fair value vested and distributed to participants					$0.10

Restricted_Stock_Performance_S2

Restricted Stock, Performance Share and Cash Awards - Additional Information (Detail) (USD $)

12 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Mar. 12, 2014

Mar. 13, 2013

Mar. 16, 2012

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2012

Sep. 30, 2014

12-May-14

Dec. 31, 2011

12-May-09

Mar. 08, 2011

Times

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Share-based compensation, shares outstanding

8,400,000

8,300,000

9,000,000

10,600,000

Shares granted in the period

376,541

369,975

361,400

Ultimate award value, multiples of original value of the units, minimum

0.5

Ultimate award value, multiples of original value of the units, maximum

1.5

Scenario, Forecast [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Provisional compensation cash award approved for future grant by compensation committee, units

220,000

Minimum [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Period of Service from Grant Date Stock Options Awarded Not Subject to Forfeiture

2 years

Executive Officer [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Minimum age of employee with not subject to award forfeiture on condition compliance

55 years

Officer and Key Employees [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Stock options granted, exercise percentage, year one

34.00%

Stock options granted, exercise percentage, year two

33.00%

Stock options granted, exercise percentage, year three

33.00%

Provisional compensation cash award approved for future grant by compensation committee, units

229,000

Restricted Stock Units (RSUs) [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Share-based compensation, shares outstanding, Value

2,000,000

Share-based compensation, shares outstanding

2,000,000

Share based payment award vesting date

12-Mar-18

13-Mar-17

16-Mar-16

Restricted stock or unit expense

12,700,000

9,800,000

7,100,000

Restricted Stock Units (RSUs) [Member] | Minimum [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Period of Service from Grant Date Stock Options Awarded Not Subject to Forfeiture

2 years

Restricted Stock Units (RSUs) [Member] | Executive Officer [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Minimum age of employee with not subject to award forfeiture on condition compliance

55 years

Restricted Stock Plan [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Shares authorized

4,000,000

Shares granted in the period

342,850

369,975

361,400

323,550

345,000

332,000

33,741

Fair value of grants in period

16,000,000

14,600,000

12,900,000

1,500,000

Stock options granted, exercise percentage, year one

34.00%

Stock options granted, exercise percentage, year two

33.00%

Stock options granted, exercise percentage, year three

33.00%

Unvested Restricted Stock [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Total intrinsic value

57,300,000

49,500,000

Equity awards with an aggregate fair value

10,000,000

8,400,000

Cash Awards [Member] | Officer and Key Employees [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Performance period, years

1 year

Vesting period, years

2 years

Provisional compensation cash awards approved for future grant by compensation committee, value

17,600,000

10,800,000

10,500,000

13,100,000

14,400,000

Provisional compensation cash award approved for future grant by compensation committee, units

411,000

269,000

368,000

263,000

365,000

432,000

464,000

Performance Shares [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Shares authorized

48,800

Total intrinsic value

2,300,000

Performance unit awards approved, Fair value

2,300,000

Performance unit awards, Terms

Granted units for the 2014 provisional award will fully vest based on continuous employment through January 1, 2017, and will be settled in shares of our common stock on a one-for-one basis as soon as practicable in 2017.

Compensation expense

500,000

Performance period, years

1 year

Vesting period, years

2 years

2013 Provisional Cash Awards [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Cash-based compensation awards, expenses

5,900,000

2012 Provisional Cash Awards [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Cash-based compensation awards, expenses

8,400,000

7,600,000

2011 Provisional Cash Awards [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Cash-based compensation awards, expenses

10,100,000

7,500,000

2009 Provisional Cash Awards [Member]

Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]

Provisional compensation cash award approved for future grant by compensation committee, units

1,100,000

Grants vested in period fair value

26,500,000

Restricted_Stock_Performance_S3

Restricted Stock, Performance Share and Cash Awards - Schedule of Restricted Stock Awards Vesting Periods (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Vesting Period [Line Items]
Shares granted in the period	376,541	369,975	361,400
Vesting Period One Year [Member]
Vesting Period [Line Items]
Shares granted in the period	19,250	19,375	20,000
Vesting period, years	1 year
Vesting Period Three Years [Member]
Vesting Period [Line Items]
Shares granted in the period	33,741
Vesting period, years	3 years
Vesting Period Four Years [Member]
Vesting Period [Line Items]
Shares granted in the period	323,550	345,000	332,000
Vesting period, years	4 years
Vesting Period Five Years [Member]
Vesting Period [Line Items]
Shares granted in the period		5,600	9,400
Vesting period, years	5 years

Retirement_Plan_Reconciliation

Retirement Plan - Reconciliation of Balances of Pension Benefit Obligation And Fair Value of Plan Assets (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Benefit obligation at beginning of year		$272.50	$292
Service cost		0.7	0.6	0.4
Interest cost		12.7	11.7	11.8
Net actuarial loss (gain)		56.8	-22.4
Partial plan settlement loss		-16.7
Benefits paid	-43.3	-54	-9.4
Benefit obligation at end of year	272	272	272.5	292
Fair value of plan assets at beginning of year		254.9	227.4
Actual return on plan assets		16.3	30.6
Contributions by the company			6.3
Benefits paid	-43.3	-54	-9.4
Fair value of plan assets at end of year	217.2	217.2	254.9	227.4
Funded status of the plan (underfunded)	-54.8	-54.8	-17.6
Noncurrent liabilities - accrued benefit liability	-54.8	-54.8	-17.6
Accumulated other comprehensive loss - net actuarial loss	75.2	75.2	47
Net amount included in retained earnings	$20.40	$20.40	$29.40

Retirement_Plans_Components_of

Retirement Plans - Components of Net Periodic Pension Benefit Cost and Other Changes in Plan Assets and Obligations Recognized in Earnings and Other Comprehensive Earnings (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Service cost	$0.70	$0.60	$0.40
Interest cost on benefit obligation	12.7	11.7	11.8
Expected return on plan assets	-18.7	-17	-15.2
Amortization of net loss	2.3	7.9	7.2
Settlement	12
Net periodic benefit cost (earnings)	9	3.2	4.2
Net loss (gain) incurred	42.5	-36	10.6
Settlement recognition	-12
Amortization of net loss	-2.3	-7.9	-7.2
Total recognized in other comprehensive loss (earnings)	28.2	-43.9	3.4
Total recognized in net periodic pension cost (earnings) and other comprehensive loss (earnings)	37.2	-40.7	7.6
Amortization of net loss, Estimated	$6	$2.40	$7.70

Retirement_Plan_Weighted_Avera

Retirement Plan - Weighted Average Assumptions of Pension Benefit Obligation and Net Periodic Pension Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Discount rate, pension benefit obligation	4.00%	4.75%
Weighted average expected long-term rate of return on plan assets, pension benefit obligation	7.50%	7.50%
Discount rate, net periodic pension benefit cost	4.75%	4.00%	4.50%
Weighted average expected long-term rate of return on plan assets, net periodic pension benefit cost	7.50%	7.50%	7.50%

Retirement_Plans_Schedule_of_B

Retirement Plans - Schedule of Benefit Payments Expected to be Paid by Plan (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
2015	$10.80
2016	11.3
2017	11.8
2018	12.3
2019	12.9
Years 2020 to 2024	$73.30

Retirement_Plans_Summary_of_Pl

Retirement Plans - Summary of Plan's Weighted Average Asset Allocations (Detail)	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Total weighted average asset	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total weighted average asset	65.00%	69.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total weighted average asset	26.00%	24.00%
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total weighted average asset	9.00%	7.00%

Retirement_Plans_Additional_In

Retirement Plans - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2014	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Employees	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Expected period of return on plan assets, years			10 years	10 years
Discretionary contributions by employer				$6,300,000	$7,200,000
Minimum contribution by employer			0	0	0
Aggregate lump sum payout		43,300,000	54,000,000	9,400,000
Number of employees covered in the plan	2,500
Defined benefit plan, description			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.
Defined benefit plan benefit obligation period increase (decrease)			-60,000,000
Defined benefit plan obligation (improvement to pension underfunding)			17,000,000
Non-cash settlement charge, pretax		12,000,000
Fair value of plan assets		217,200,000	217,200,000	254,900,000	227,400,000
Postretirement benefit obligation and unfunded status of plan		272,000,000	272,000,000	272,500,000	292,000,000
Net periodic postretirement benefit cost			9,000,000	3,200,000	4,200,000
Foreign Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible compensation for matching contributions by employer			5.00%
Contribution expense to plan			29,700,000	18,100,000	16,000,000
Matching contributions by employer, percentage			100.00%
Additional percentage of eligible compensation for matching contributions by employer			5.00%
Qualified Contributory Savings and Thrift 401(k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible compensation for matching contributions by employer			5.00%
Contribution expense to plan			38,000,000	36,800,000	33,000,000
Matching contributions by employer, percentage			100.00%
Matching contributions vesting schedule			5 years
Nonqualified Deferred Compensation Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible compensation for matching contributions by employer			5.00%
Contribution expense to plan			3,700,000	2,800,000	2,500,000
Fair value of plan assets		177,500,000	177,500,000	148,200,000
Retiree Health Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Postretirement benefit obligation and unfunded status of plan		4,100,000	4,100,000	3,100,000
Net periodic postretirement benefit cost			($500,000)	($500,000)	($100,000)

Retirement_Plans_Summary_of_Pl1

Retirement Plans - Summary of Plan's Assets Carried at Fair Value (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Total fair value	$217.20	$254.90	$227.40
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	116.1	158.8
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	$101.10	$96.10	$91.10

Retirement_Plans_Reconciliatio

Retirement Plans - Reconciliation of Beginning and Ending Balances for Level 3 Assets of Plan Measured at Fair Value (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year			$227.40
Fair value of plan assets at end of year	217.2	254.9	227.4
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	96.1	91.1
Settlements	0	0
Unrealized gains	5	5
Fair value of plan assets at end of year	$101.10	$96.10

Investments_Investments_Report

Investments - Investments Reported in Other Current and Non-Current Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Assets	$82	$90.40
Funding Commitments	2.9
Chem-Mod LLC [Member]
Schedule of Equity Method Investments [Line Items]
Assets	4	4
Funding Commitments	0
Chem-Mod International LLC [Member]
Schedule of Equity Method Investments [Line Items]
Assets	2	2
Funding Commitments	0
C-Quest Technology LLC and C-Quest Technologies International LLC [Member]
Schedule of Equity Method Investments [Line Items]
Assets	0	2
Funding Commitments	0
Clean-Coal Investments [Member] \| Controlling Interest [Member] \| Fourteen 2009 Era Clean Coal Plants [Member]
Schedule of Equity Method Investments [Line Items]
Assets	17.3	18.3
Funding Commitments	0
Clean-Coal Investments [Member] \| Controlling Interest [Member] \| Nineteen 2011 Era Clean Coal Plants [Member]
Schedule of Equity Method Investments [Line Items]
Assets	54.5	59.3
Funding Commitments	0
Clean-Coal Investments [Member] \| Non-controlling Interest [Member] \| One 2011 Era Clean Coal Plant [Member]
Schedule of Equity Method Investments [Line Items]
Assets	1	1.1
Funding Commitments	0
Other Investments [Member]
Schedule of Equity Method Investments [Line Items]
Assets	3.2	3.7
Funding Commitments	$2.90

Investments_Investments_Report1

Investments - Investments Reported in Other Current and Non-Current Assets (Parenthetical) (Detail) (Clean-Coal Investments [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	Plant	Plant
	Entity	Entity
Schedule of Equity Method Investments [Line Items]
Number of variable interest entities	1
Fourteen 2009 Era Clean Coal Plants [Member] \| Controlling Interest [Member]
Schedule of Equity Method Investments [Line Items]
Number of coal plants	14	14
Number of variable interest entities	5	5
One 2011 Era Clean Coal Plant [Member] \| Non-controlling Interest [Member]
Schedule of Equity Method Investments [Line Items]
Number of coal plants	1	1
Number of variable interest entities	1	1
Nineteen 2011 Era Clean Coal Plants [Member] \| Controlling Interest [Member]
Schedule of Equity Method Investments [Line Items]
Number of coal plants	19	19
Number of variable interest entities	13	13

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 01, 2013	Mar. 31, 2014	Aug. 01, 2013
Schedule of Equity Method Investments [Line Items]
Ownership interest held	50.00%	99.00%
Chem-Mod Clean-Coal Venture [Member]
Schedule of Equity Method Investments [Line Items]
Total assets of variable interest entities	$10.20
Total liabilities of variable interest entities	1.2
Total revenue of limited liability companies	69.1
Total expenses of limited liability companies	38.4
Non-controlling interest	35.3
Chem-Mod International LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest held	31.52%
C-Quest Technology LLC and C-Quest Technologies International LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest held	12.00%
Increase in ownership interest	4.00%
Option to acquire additional interest, percent	19.00%
Option to acquire additional interest, total price	9.5
End date for acquiring additional interest	1-Aug-16
Loans to majority owners				2
Interest rate of loan				2.00%
Maturity date of of loan	15-May-14
Loan description	On August 1, 2013, we loaned the majority owner $2.0 million at a 2% interest rate, which was to mature on May 15, 2014. Also on August 1, 2013, the option to acquire the 19% interests was extended to August 15, 2016. The loan was to be repaid in cash or by delivery of an additional 4% ownership interest in C-Questbs global entities. On March 31, 2014, we accepted payment of the loan by delivery of the additional 4% ownership interest, therefore our remaining option was reduced to 15% and the remaining purchase price was reduced to $7.5 million.
Delivery of additional ownership interest			4.00%
C-Quest Technology LLC and C-Quest Technologies International LLC [Member] \| Change in Option on Delivery of Additional Interest [Member]
Schedule of Equity Method Investments [Line Items]
Option to acquire additional interest, percent	15.00%
Option to acquire additional interest, total price	$7.50
Chem-Mod Clean-Coal Venture - U.S. and Canadian Operations [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest held	46.54%

Investments_Clean_Coal_Investm

Investments - Clean Coal Investments - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 01, 2013	Mar. 01, 2014	Mar. 01, 2013
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Plant	Dec. 31, 2013	Dec. 31, 2012	Sep. 01, 2013	Mar. 01, 2014	Plant
Schedule of Equity Method Investments [Line Items]
Total revenues	$1,245.40	$1,286.80	$1,179.30	$915	$890.20	$835.80	$779.50	$674.10	$4,626.50	$3,179.60	$2,520.30
Total expenses	-1,219.10	-1,199.10	-1,072.20	-868.7	-840.9	-750.3	-682.1	-631.8	4,359.10	2,905.10	2,275
Ownership interest acquired in a limited liability company	50.00%								50.00%			99.00%
Amount of promissory note												10
Purchase price paid in cash												4
Number of clean coal production plants seeking and negotiating for long term production contract									8
Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value of prior non-controlling interest in limited liability company on acquisition date													15.6
Ownership interest acquired in a limited liability company	50.00%								50.00%
Notes Payable, Other Payables [Member]
Schedule of Equity Method Investments [Line Items]
Interest rate on promissory note												3.00%
2009 Era Plants [Member]
Schedule of Equity Method Investments [Line Items]
Number of additional plants acquired													7	12
Number of additional plants acquired with ownership interest range one														9
Number of additional plants acquired with ownership interest range two														3
Ownership interest before additional nine plants acquired														24.50%
Ownership interest after additional nine plants acquired														49.50%
Ownership interest before additional three plants acquired														25.00%
Ownership interest after additional three plants acquired														60.00%
Total revenues									260.9	128.3
Total expenses									264.3	133.5
Purchase of consideration received	8								8
Payment of cash and other consideration	5								5
Gain on purchase of additional interest	11.4								11.4
Prior percentage of equity interest in limited liability company	25.00%								25.00%
Additional percentage of equity interest in limited liability company upon acquisition	35.00%								35.00%
Fixed assets and other amortizable intangible assets acquired upon acquisition	26.3								26.3
Carrying value of prior non-controlling interest in limited liability company on acquisition date	4.8								4.8
Other assets acquired upon acquisition	6.8								6.8
Ownership interest before additional seven plants acquired													49.50%
Ownership interest after additional seven plants acquired													100.00%
2011 Era Plants [Member]
Schedule of Equity Method Investments [Line Items]
Number of additional plants acquired													5
Total revenues									381.6
Total expenses									405.7
Gain on purchase of additional interest													25.6
Fixed assets and other amortizable intangible assets acquired upon acquisition													26.3
Ownership interest before additional one plant acquired													48.80%
Ownership interest after additional one plant acquired													90.00%
Ownership interest before additional three plants acquired													49.00%
Ownership interest after additional three plants acquired													100.00%
Ownership interest before additional one plant acquired													98.00%
Ownership interest after additional one plant acquired													100.00%
2011 Era Plants [Member] \| Notes Payable, Other Payables [Member]
Schedule of Equity Method Investments [Line Items]
Total revenues									84	33.7
Total expenses									93	36.9
Chem-Mod LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of clean coal production plants owned									34
Chem-Mod LLC [Member] \| 2009 Era Plants [Member]
Schedule of Equity Method Investments [Line Items]
Number of clean coal production plants owned									14
Chem-Mod LLC [Member] \| 2011 Era Plants [Member]
Schedule of Equity Method Investments [Line Items]
Number of clean coal production plants owned									20
Long Term Production Contracts [Member]
Schedule of Equity Method Investments [Line Items]
Number of clean coal production plants owned									26
Clean-Coal Investments [Member]
Schedule of Equity Method Investments [Line Items]
Number of variable interest entities	1								1
Clean-Coal Investments [Member] \| VIE [Member]
Schedule of Equity Method Investments [Line Items]
Total assets of limited liability companies	4.4								4.4
Total liability of limited liability companies	1.4								1.4
Total revenues of limited liability companies									33.4
Total expenses of limited liability companies									$41

Investments_Other_Investments_

Investments - Other Investments - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Sep. 01, 2013
In Millions, unless otherwise specified	Investment	Dec. 31, 2013	Sep. 01, 2013
Schedule of Equity Method Investments [Line Items]
Assets	$82	$90.40
Ownership interest held	50.00%		99.00%
Non controlling interest certified low-income housing developments	12
Non controlling interest in real estate entities	2
Carrying value of investments in real estate entities	0
Other Investments [Member]
Schedule of Equity Method Investments [Line Items]
Assets	3.2	3.7
Other Investments [Member] \| Four Venture Capital Funds [Member]
Schedule of Equity Method Investments [Line Items]
Assets	3.2
Non controlling interest in venture capital funds number	4
Other Investments [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Equity Method Investments [Line Items]
Assets	60
Debt	20
Other Investments [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member] \| Twelve Certified Low-Income Housing Developments [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value of investments	0
Investment Management Company [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest held	20.00%
Cost of acquiring equity interest	$0.50

Commitments_Contingencies_and_2

Commitments, Contingencies and Off-Balance Sheet Arrangements - Contractual Obligations (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Note Purchase Agreements [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015
Contractual Obligations, Payments Due by Period, 2016	50
Contractual Obligations, Payments Due by Period, 2017	300
Contractual Obligations, Payments Due by Period, 2018	100
Contractual Obligations, Payments Due by Period, 2019	100
Contractual Obligations, Payments Due by Period, Thereafter	1,575
Contractual Obligations, Payments Due by Period, Total	2,125
Multi Currency Credit Agreement [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	140
Contractual Obligations, Payments Due by Period, 2016
Contractual Obligations, Payments Due by Period, 2017
Contractual Obligations, Payments Due by Period, 2018
Contractual Obligations, Payments Due by Period, 2019
Contractual Obligations, Payments Due by Period, Thereafter
Contractual Obligations, Payments Due by Period, Total	140
Premium Financing Debt Facility [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	127.9
Contractual Obligations, Payments Due by Period, 2016
Contractual Obligations, Payments Due by Period, 2017
Contractual Obligations, Payments Due by Period, 2018
Contractual Obligations, Payments Due by Period, 2019
Contractual Obligations, Payments Due by Period, Thereafter
Contractual Obligations, Payments Due by Period, Total	127.9
Total Debt Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	368.8
Contractual Obligations, Payments Due by Period, 2016	150.4
Contractual Obligations, Payments Due by Period, 2017	397.5
Contractual Obligations, Payments Due by Period, 2018	177.5
Contractual Obligations, Payments Due by Period, 2019	173.2
Contractual Obligations, Payments Due by Period, Thereafter	1,898.90
Contractual Obligations, Payments Due by Period, Total	3,166.30
Operating Lease Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	99
Contractual Obligations, Payments Due by Period, 2016	81.7
Contractual Obligations, Payments Due by Period, 2017	68.7
Contractual Obligations, Payments Due by Period, 2018	49.8
Contractual Obligations, Payments Due by Period, 2019	38.8
Contractual Obligations, Payments Due by Period, Thereafter	131.3
Contractual Obligations, Payments Due by Period, Total	469.3
Less Sublease Arrangements [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	-1.4
Contractual Obligations, Payments Due by Period, 2016	-0.7
Contractual Obligations, Payments Due by Period, 2017	-0.3
Contractual Obligations, Payments Due by Period, 2018	-0.1
Contractual Obligations, Payments Due by Period, 2019
Contractual Obligations, Payments Due by Period, Thereafter
Contractual Obligations, Payments Due by Period, Total	-2.5
Outstanding Purchase Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	29.7
Contractual Obligations, Payments Due by Period, 2016	5.4
Contractual Obligations, Payments Due by Period, 2017	0.9
Contractual Obligations, Payments Due by Period, 2018	0.3
Contractual Obligations, Payments Due by Period, 2019
Contractual Obligations, Payments Due by Period, Thereafter
Contractual Obligations, Payments Due by Period, Total	36.3
Total Contractual Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	496.1
Contractual Obligations, Payments Due by Period, 2016	236.8
Contractual Obligations, Payments Due by Period, 2017	466.8
Contractual Obligations, Payments Due by Period, 2018	227.5
Contractual Obligations, Payments Due by Period, 2019	212
Contractual Obligations, Payments Due by Period, Thereafter	2,030.20
Contractual Obligations, Payments Due by Period, Total	3,669.40
Interest on Debt [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2015	100.9
Contractual Obligations, Payments Due by Period, 2016	100.4
Contractual Obligations, Payments Due by Period, 2017	97.5
Contractual Obligations, Payments Due by Period, 2018	77.5
Contractual Obligations, Payments Due by Period, 2019	73.2
Contractual Obligations, Payments Due by Period, Thereafter	323.9
Contractual Obligations, Payments Due by Period, Total	$773.40

Commitments_Contingencies_and_3

Commitments, Contingencies and Off-Balance Sheet Arrangements - Additional Information (Detail) (USD $)	12 Months Ended			156 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
	Entity	Entity	Entity	Entity
	sqft
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Acquired property through lease area, sqft	306,000
Acquired property through lease percentage of building	60.00%
Operating lease commitment, expiration date	28-Feb-18
Total rent expense	$122	$91.30	$91
Number of companies acquired	67	79	46	339
Aggregate amount of maximum earnout obligations related to acquisitions	549.8	462.3
Aggregate amount of maximum earnout obligations related to acquisitions, recorded in consolidated balance sheet	205.3	162.7
Liabilities recorded on self-insurance	9.7			9.7
Debt	46.1			46.1
Income tax credits and adjustments	117
Tax-Advantaged Investments No Longer Held [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Total indemnifications	32			32
Letter of Credit [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Debt	5			5
Number of letters of credit issued	1
Self-Insurance Deductibles [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Number of letters of credit issued	2
Self-Insurance Deductibles [Member] \| Letter of Credit [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Liabilities recorded on self-insurance	11.3			11.3
Debt	9.7			9.7
Rent-A-Captive Facility [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Number of letters of credit issued	7
Rent-A-Captive Facility [Member] \| Letter of Credit [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Debt	6.3			6.3
Errors and Omissions [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Insurance claims, amount retained	5
Amount of losses in excess of retained amounts	175			175
Minimum [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Ownership interest	1.00%			1.00%
Number of micro-captive insurance companies organized or managed	100
Minimum [Member] \| Errors and Omissions [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Actuarial range value	1.4			1.4
Maximum [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Ownership interest	50.00%			50.00%
Maximum [Member] \| Errors and Omissions [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Actuarial range value	$6.20			$6.20

Commitments_Contingencies_and_4

Commitments, Contingencies and Off-Balance Sheet Arrangements - Off-Balance Sheet Commitments (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2015	$0.80
Amount of Commitment Expiration by Period - 2016	0.8
Amount of Commitment Expiration by Period - 2017	0.8
Amount of Commitment Expiration by Period - 2018	0.8
Amount of Commitment Expiration by Period - 2019	0.9
Amount of Commitment Expiration by Period - Thereafter	42
Total Amounts Committed	46.1
Letters of Credit [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2015	0
Amount of Commitment Expiration by Period - 2016	0
Amount of Commitment Expiration by Period - 2017	0
Amount of Commitment Expiration by Period - 2018	0
Amount of Commitment Expiration by Period - 2019	0
Amount of Commitment Expiration by Period - Thereafter	22.6
Total Amounts Committed	22.6
Financial Guarantees [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2015	0.8
Amount of Commitment Expiration by Period - 2016	0.8
Amount of Commitment Expiration by Period - 2017	0.8
Amount of Commitment Expiration by Period - 2018	0.8
Amount of Commitment Expiration by Period - 2019	0.9
Amount of Commitment Expiration by Period - Thereafter	16.5
Total Amounts Committed	20.6
Funding Commitments [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2015	0
Amount of Commitment Expiration by Period - 2016	0
Amount of Commitment Expiration by Period - 2017	0
Amount of Commitment Expiration by Period - 2018	0
Amount of Commitment Expiration by Period - 2019	0
Amount of Commitment Expiration by Period - Thereafter	2.9
Total Amounts Committed	$2.90

Commitments_Contingencies_and_5

Commitments, Contingencies and Off-Balance Sheet Arrangements - Outstanding Letters of Credit, Financial Guarantees and Funding Commitments (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Maximum Exposure	$46.10
Liability Recorded	9.7
Funding Commitment To Two Funds Expire In 2019 And 2023 Trigger [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Collateral	None
Compensation to Us	None
Maximum Exposure	2.9
Credit Support Under Letters Of Credit For Deductibles Due By Us On Our Own Insurance Coverage's Expires After 2019 Trigger [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Collateral	None
Compensation to Us	None
Maximum Exposure	11.3
Liability Recorded	9.7
Credit Enhancement Under Letters Of Credit For Our Captive Insurance Operations To Meet Minimum Statutory Capital Requirements Expires After 2019 [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Collateral	None
Compensation to Us	Reimbursement of LOC fees
Maximum Exposure	6.3
Credit Support Under Letters Of Credit For Clients Claim Funds Held By Our Bermuda Captive Insurance Operation In Fiduciary Capacity Expires After 2019 [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Collateral	None
Compensation to Us	Reimbursement of LOC fees
Maximum Exposure	5
Financial Guarantee Of Mortgage Loan To UK Based Employee Expires When Mortgage Balance Reduced Trigger [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Compensation to Us	None
Maximum Exposure	9.1
Financial Guarantees Of Loans To Thirty Seven Canadian Based Employees Expires When Loan Balances Reduced Trigger [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Compensation to Us	None
Maximum Exposure	$11.50

Commitments_Contingencies_and_6

Commitments, Contingencies and Off-Balance Sheet Arrangements - Outstanding Letters of Credit, Financial Guarantees and Funding Commitments (Parenthetical) (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Funding commitment to fund, expires in 2019	$1.50
Funding commitment to fund, expires in 2023	1.4
Financial Guarantee Of Mortgage Loan To UK Based Employee Expires When Mortgage Balance Reduced Trigger [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Decrease in long term mortgage debt	6.4
Long Term Debt Mortgages	$11

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense Benefit [Line Items]
Earnings before income taxes, foreign	$2.50	$43.70	$10.60
Interest expense, foreign deposits	76.5	16.6
Interest expense, domestic deposits	76.5	16.6
Net unrecognized tax benefits	8.2	5.9
Accrued interest and penalties related to unrecognized tax benefits	0.8	0.6
Deferred tax assets	494.8	364.7
Deferred tax liabilities	378.4	209.5
Deferred minimum tax credits	108.2
Deferred business tax credits	124.3
Deferred other tax credits	0.9
Undistributed earnings of foreign subsidiaries	279.9	224.2
Unrecognized deferred tax liability on undistributed earnings	36.2	35.2
Other Current Assets [Member]
Income Tax Expense Benefit [Line Items]
Deferred tax assets	102.2	84.9
Other Current Liabilities [Member]
Income Tax Expense Benefit [Line Items]
Deferred tax assets	4.3	5
Noncurrent Liabilities [Member]
Income Tax Expense Benefit [Line Items]
Deferred tax liabilities	$374.10	$204.50

Income_Taxes_Components_of_Ear

Income Taxes - Components of Earnings Before Income Taxes and Provision for Income Taxes (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Domestic									$264.90	$230.80	$234.70
Foreign, principally Australia, Canada, New Zealand and the U.K.									2.5	43.7	10.6
Earnings before income taxes	26.3	87.7	107.1	46.3	49.3	85.5	97.4	42.3	267.4	274.5	245.3
Federal Current									38.8	29	45.4
Federal Deferred									-96.6	-47.7	-14.6
Total Provision (benefit) for income taxes, Federal									-57.8	-18.7	30.8
State and local Current									19.5	10.6	17.3
State and local Deferred									-1.1	-0.6	-2.9
Total Provision (benefit) for income taxes, State and local									18.4	10	14.4
Foreign Current									30.5	28.5	8.7
Foreign Deferred									-27.1	-13.9	-3.6
Total Provision (benefit) for income taxes, Foreign									3.4	14.6	5.1
Provision (benefit) for income taxes									($36)	$5.90	$50.30

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Provision for Income Taxes with Federal Statutory Income Tax Rate (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Federal statutory rate	$93.60	$96.10	$85.90
State income taxes - net of Federal benefit	12	6.5	9.4
Foreign taxes	0.8	-0.8	0.9
Alternative energy, foreign and other tax credits	-145.5	-93.8	-45.3
Foreign dividends and other permanent differences	-6.1	-2.5	-2.7
Nondeductible employee compensation	5.4
Changes in unrecognized tax benefits	2.4	1.5	0.6
Change in valuation allowance		0.5	0.3
Other	1.4	-1.6	1.2
Provision (benefit) for income taxes	($36)	$5.90	$50.30
Federal statutory rate, % of Pretax Earnings	35.00%	35.00%	35.00%
State income taxes-net of Federal benefit, % of Pretax Earnings	4.50%	2.40%	3.80%
Foreign taxes, % of Pretax Earnings	0.30%	-0.30%	0.40%
Alternative energy, foreign and other tax credits, % of Pretax Earnings	-54.40%	-34.20%	-18.50%
Foreign dividends and other permanent differences, % of Pretax Earnings	-2.30%	-0.90%	-1.10%
Nondeductible employee compensation, % of Pretax Earnings	2.00%
Changes in unrecognized tax benefits, % of Pretax Earnings	0.90%	0.50%	0.20%
Change in valuation allowance, % of Pretax Earnings		0.20%	0.10%
Other, % of Pretax Earnings	0.50%	-0.60%	0.60%
Total provision (benefit) for income taxes-continuing operations, % of Pretax Earnings	-13.50%	2.10%	20.50%

Income_Taxes_Gross_Unrecognize

Income Taxes - Gross Unrecognized Tax Benefit (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits at January 1	$9.20	$6.70
Increases in tax positions for current year	2.6	2.9
Settlements	0	0
Lapse in statute of limitations	-1	-1.4
Increases in tax positions for prior years	1.7	2.3
Decreases in tax positions for prior years		-1.3
Gross unrecognized tax benefits at December 31	$12.50	$9.20

Income_Taxes_Deferred_Tax_Asse

Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Alternative minimum tax and other credit carryforwards	$233.40	$147.40
Accrued and unfunded compensation and employee benefits	166.9	136.6
Amortizable intangible assets	66.7	12.5
Compensation expense related to stock options	14.7	14.2
Accrued liabilities	31	30.2
Accrued pension liability	24.3	9.2
Investments	10	9
Net operating loss carryforwards	10	11.9
Deferred rent liability	8.5	8.2
Other	4.8	6.8
Total deferred tax assets	570.3	386
Valuation allowance for deferred tax assets	-75.5	-21.3
Deferred tax assets	494.8	364.7
Nondeductible amortizable intangible assets	338.7	184
Investment-related partnerships	26.6	13.2
Depreciable fixed assets	8.8	5.2
Other prepaid items	4.3	4.7
Accrued liabilities		2.4
Total deferred tax liabilities	378.4	209.5
Net deferred tax assets	$116.40	$155.20

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Earnings - Schedule of Accumulated Comprehensive Earnings (Loss) (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Ending Balance	($260.60)	($2.60)
Pension Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	-25.6	-52.4	-49
Net change in period	-18.6	26.8	-3.4
Ending Balance	-44.2	-25.6	-52.4
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	22.1	20.5	4.4
Net change in period	-238.4	1.6	16.1
Ending Balance	-216.3	22.1	20.5
Fair Value of Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	0.9	-0.9	-2.6
Net change in period	-1	1.8	1.7
Ending Balance	-0.1	0.9	-0.9
Accumulated Other Comprehensive Earnings (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	-2.6	-32.8	-47.2
Net change in period	-258	30.2	14.4
Ending Balance	($260.60)	($2.60)	($32.80)

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Earnings - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Expense related to pension liability reclassified from accumulated other comprehensive loss	$14.30	$7.90	$7.20
Expense related to fair value of derivative investments reclassified from accumulated other comprehensive loss	0.6	0.9	0.2
Foreign currency translation reclassified from accumulated other comprehensive loss	$0	$0	$0

Recovered_Sheet1

Quarterly Operating Results (Unaudited) - Quarterly Operating Results (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Total revenues	$1,245.40	$1,286.80	$1,179.30	$915	$890.20	$835.80	$779.50	$674.10	$4,626.50	$3,179.60	$2,520.30
Total expenses	1,219.10	1,199.10	1,072.20	868.7	840.9	750.3	682.1	631.8	-4,359.10	-2,905.10	-2,275
Earnings before income taxes	26.3	87.7	107.1	46.3	49.3	85.5	97.4	42.3	267.4	274.5	245.3
Net earnings	$51.50	$93.60	$109	$49.30	$60	$74.60	$93.50	$40.50	$303.40	$268.60	$195
Basic net earnings per share:	$0.32	$0.58	$0.71	$0.37	$0.45	$0.57	$0.73	$0.32
Diluted net earnings per share:	$0.31	$0.58	$0.70	$0.36	$0.45	$0.57	$0.73	$0.32

Segment_Information_Additional

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Segment
Segment Reporting [Abstract]
Number of reportable operating segments	3

Segment_Information_Schedule_o

Segment Information - Schedule of Segment Reporting Information by Segment (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Commissions									$2,083	$1,553.10	$1,302.50
Fees									1,258.30	1,059.50	971.7
Supplemental commissions									104	77.3	67.9
Contingent commissions									84.7	52.1	42.9
Investment income									41.3	8.1	10.4
Gains on books of business sales and other									7.3	5.2	3.9
Revenue from clean coal activities									1,029.50	412.5	119.6
Other - net gain									18.4	11.8	1.4
Total revenues	1,245.40	1,286.80	1,179.30	915	890.2	835.8	779.5	674.1	4,626.50	3,179.60	2,520.30
Compensation									2,167.60	1,685	1,493.40
Operating									767.2	552.4	483.2
Cost of revenues from clean coal activities									1,058.90	437.3	111.6
Interest									89	50.1	43
Depreciation									69.4	53.4	41.4
Amortization									189.5	125.2	99
Change in estimated acquisition earnout payables									17.5	1.7	3.4
Total expenses	-1,219.10	-1,199.10	-1,072.20	-868.7	-840.9	-750.3	-682.1	-631.8	4,359.10	2,905.10	2,275
Earnings (loss) before income taxes	26.3	87.7	107.1	46.3	49.3	85.5	97.4	42.3	267.4	274.5	245.3
Provision (benefit) for income taxes									-36	5.9	50.3
Net earnings (loss)									303.4	268.6	195
Net foreign exchange gain (loss)									0.5	0.2	-1.9
Total revenues	1,245.40	1,286.80	1,179.30	915	890.2	835.8	779.5	674.1	4,626.50	3,179.60	2,520.30
Total assets	10,010				6,860.50				10,010	6,860.50	5,352.30
Goodwill - net	3,449.60				2,145.20				3,449.60	2,145.20	1,472.70
Amortizable intangible assets - net	1,776				1,078.80				1,776	1,078.80	809.6
Brokerage [Member]
Segment Reporting Information [Line Items]
Goodwill - net	3,427.50				2,122.90				3,427.50	2,122.90	1,451.40
Risk Management [Member]
Segment Reporting Information [Line Items]
Goodwill - net	22.1				22.3				22.1	22.3	21.3
Corporate [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0	0
Unites States [Member]
Segment Reporting Information [Line Items]
Total revenues									3,454.90	2,542.60	2,006.10
Total revenues									3,454.90	2,542.60	2,006.10
Total assets	5,046.60				4,422.40				5,046.60	4,422.40	3,675.90
Goodwill - net	1,672.80				1,469.80				1,672.80	1,469.80
Unites States [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Goodwill - net	1,652.60				1,449.60				1,652.60	1,449.60
Unites States [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Goodwill - net	20.2				20.2				20.2	20.2
Unites States [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total revenues									726.4	427.9	346
Total revenues									726.4	427.9	346
Total assets					1,878.30					1,878.30	1,170
Goodwill - net	820.6				584.9				820.6	584.9
United Kingdom [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Goodwill - net	818.7				582.8				818.7	582.8
United Kingdom [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Goodwill - net	1.9				2.1				1.9	2.1
United Kingdom [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Australia [Member]
Segment Reporting Information [Line Items]
Total revenues									243.1	152.6	121.4
Total revenues									243.1	152.6	121.4
Total assets	642				277.9				642	277.9	260.5
Goodwill - net	336.8				37.1				336.8	37.1
Australia [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Goodwill - net	336.8				37.1				336.8	37.1
Australia [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Australia [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Canada [Member]
Segment Reporting Information [Line Items]
Total revenues									85	32.6	32.1
Total revenues									85	32.6	32.1
Total assets	1,031.20				108.8				1,031.20	108.8	102.4
Goodwill - net	318.5				26.8				318.5	26.8
Canada [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Goodwill - net	318.5				26.8				318.5	26.8
Canada [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Canada [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Other Foreign, Principally New Zealand [Member]
Segment Reporting Information [Line Items]
Total revenues									117.1
Total revenues									117.1
Total assets	839.8								839.8
Goodwill - net	300.9				26.6				300.9	26.6
Other Foreign, Principally New Zealand [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Goodwill - net	300.9				26.6				300.9	26.6
Other Foreign, Principally New Zealand [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Other Foreign, Principally New Zealand [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Goodwill - net	0				0				0	0
Other Foreign, Principally Bermuda [Member]
Segment Reporting Information [Line Items]
Total revenues										23.9	14.7
Total revenues										23.9	14.7
Total assets					173.1					173.1	143.5
Operating Segments [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Commissions									2,083	1,553.10	1,302.50
Fees									595	450.5	403.2
Supplemental commissions									104	77.3	67.9
Contingent commissions									84.7	52.1	42.9
Investment income									40.3	6.1	7.2
Gains on books of business sales and other									7.3	5.2	3.9
Total revenues									2,914.30	2,144.30	1,827.60
Compensation									1,715.70	1,290.40	1,131.60
Operating									534.1	369.9	312.7
Depreciation									44.7	31.1	24.7
Amortization									186.7	122.7	96.2
Change in estimated acquisition earnout payables									17.5	2.6	3.6
Total expenses									2,498.70	1,816.70	1,568.80
Earnings (loss) before income taxes									415.6	327.6	258.8
Provision (benefit) for income taxes									151.8	122.8	103
Net earnings (loss)									263.8	204.8	155.8
Net foreign exchange gain (loss)									1.1	0.6	-1.6
Total revenues									2,914.30	2,144.30	1,827.60
Total assets	8,413.40				5,522.70				8,413.40	5,522.70	4,196.80
Goodwill - net	3,427.50				2,122.90				3,427.50	2,122.90	1,451.40
Amortizable intangible assets - net	1,761.20				1,061.60				1,761.20	1,061.60	791.6
Operating Segments [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Fees									663.3	609	568.5
Investment income									1	2	3.2
Total revenues									664.3	611	571.7
Compensation									401.6	370.5	347
Operating									173.3	146	137.7
Depreciation									20.9	19.4	16
Amortization									2.8	2.5	2.8
Change in estimated acquisition earnout payables										-0.9	-0.2
Total expenses									598.6	537.5	503.3
Earnings (loss) before income taxes									65.7	73.5	68.4
Provision (benefit) for income taxes									24.5	27.3	25.9
Net earnings (loss)									41.2	46.2	42.5
Net foreign exchange gain (loss)											-0.1
Total revenues									664.3	611	571.7
Total assets	547.7				544.7				547.7	544.7	498.6
Goodwill - net	22.1				22.3				22.1	22.3	21.3
Amortizable intangible assets - net	14.8				17.2				14.8	17.2	18
Operating Segments [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Revenue from clean coal activities									1,029.50	412.5	119.6
Other - net gain									18.4	11.8	1.4
Total revenues									1,047.90	424.3	121
Compensation									50.3	24.1	14.8
Operating									59.8	36.5	32.8
Cost of revenues from clean coal activities									1,058.90	437.3	111.6
Interest									89	50.1	43
Depreciation									3.8	2.9	0.7
Total expenses									1,261.80	550.9	202.9
Earnings (loss) before income taxes									-213.9	-126.6	-81.9
Provision (benefit) for income taxes									-212.3	-144.2	-78.6
Net earnings (loss)									-1.6	17.6	-3.3
Net foreign exchange gain (loss)									-0.6	-0.4	-0.2
Total revenues									1,047.90	424.3	121
Total assets	1,048.90				793.1				1,048.90	793.1	656.9
Operating Segments [Member] \| Unites States [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Total revenues									1,891.30	1,644.80	1,431.60
Total revenues									1,891.30	1,644.80	1,431.60
Total assets	3,584.30				3,219.60				3,584.30	3,219.60	2,637.10
Operating Segments [Member] \| Unites States [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Total revenues									514.7	473.5	453.5
Total revenues									514.7	473.5	453.5
Total assets	430.3				419				430.3	419	390.9
Operating Segments [Member] \| Unites States [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Total revenues									1,048.90	424.3	121
Total revenues									1,048.90	424.3	121
Total assets	1,032				783.8				1,032	783.8	647.9
Operating Segments [Member] \| United Kingdom [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Total revenues									697.1	400.5	317.8
Total revenues									697.1	400.5	317.8
Total assets	2,376.40				1,819.50				2,376.40	1,819.50	1,117.60
Operating Segments [Member] \| United Kingdom [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Total revenues									29.3	27.4	28.2
Total revenues									29.3	27.4	28.2
Total assets	74				58.8				74	58.8	52.4
Operating Segments [Member] \| Australia [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Total revenues									128.9	47.1	35.1
Total revenues									128.9	47.1	35.1
Total assets	639.2				214.3				639.2	214.3	208.4
Operating Segments [Member] \| Australia [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Total revenues									114.2	105.5	86.3
Total revenues									114.2	105.5	86.3
Total assets	2.8				63.6				2.8	63.6	52.1
Operating Segments [Member] \| Canada [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Total revenues									81.8	29.5	28.9
Total revenues									81.8	29.5	28.9
Total assets	992.2				107.3				992.2	107.3	100.7
Operating Segments [Member] \| Canada [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Total revenues									3.2	3.1	3.2
Total revenues									3.2	3.1	3.2
Total assets	39				1.5				39	1.5	1.7
Operating Segments [Member] \| Other Foreign, Principally New Zealand [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Total revenues									115.2
Total revenues									115.2
Total assets	821.3								821.3
Operating Segments [Member] \| Other Foreign, Principally New Zealand [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Total revenues									2.9
Total revenues									2.9
Total assets	1.6								1.6
Operating Segments [Member] \| Other Foreign, Principally New Zealand [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Total revenues									-1
Total revenues									-1
Total assets	16.9								16.9
Operating Segments [Member] \| Other Foreign, Principally Bermuda [Member] \| Brokerage [Member]
Segment Reporting Information [Line Items]
Total revenues										22.4	14.2
Total revenues										22.4	14.2
Total assets					162					162	133
Operating Segments [Member] \| Other Foreign, Principally Bermuda [Member] \| Risk Management [Member]
Segment Reporting Information [Line Items]
Total revenues										1.5	0.5
Total revenues										1.5	0.5
Total assets					1.8					1.8	1.5
Operating Segments [Member] \| Other Foreign, Principally Bermuda [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Total assets					$9.30					$9.30	$9

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$6.70	$6.60	$4.80
Amounts Recorded in Earnings	2.7	2.7	1
Adjustments	1.3	-2.6	0.8
Balance at End of Year	10.7	6.7	6.6
Allowance for Estimated Policy Cancellations [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	4.2	4	5.2
Amounts Recorded in Earnings	-0.2	-0.2	-1.6
Adjustments	2.8	0.4	0.4
Balance at End of Year	6.8	4.2	4
Accumulated Amortization of Expiration Lists, Noncompete Agreements and Trade Names [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	544.1	419.3	321.3
Amounts Recorded in Earnings	189.5	125.2	99
Adjustments	25.2	-0.4	-1
Balance at End of Year	$758.80	$544.10	$419.30