Affiliated Managers (MGR) 10-Q 1 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 30, 2018
Document and Entity Information
Entity Registrant Name	AFFILIATED MANAGERS GROUP, INC.
Entity Central Index Key	1,004,434
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		52,672,885
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Consolidated revenue	$ 601.3	$ 585.7	$ 1,813.9	$ 1,700.9
Consolidated expenses:
Compensation and related expenses	253.6	238.7	761.3	722.9
Selling, general and administrative	102.8	91.9	314.4	269.7
Intangible amortization and impairments	30.1	21.2	76.5	65.1
Interest expense	19.6	22.1	62.6	67.6
Depreciation and other amortization	5.3	4.8	16.5	14.9
Other expenses (net)	10.2	10.9	33.4	35.9
Total consolidated expenses	421.6	389.6	1,264.7	1,176.1
Equity method income (net)	59.7	70.7	191.3	231.6
Investment and other income	11	16.1	36.7	46.7
Income before income taxes	250.4	282.9	777.2	803.1
Income tax expense	48.5	66.1	146.1	188.2
Net income	201.9	216.8	631.1	614.9
Net income (non-controlling interests)	(77)	(91.4)	(236.2)	(240.7)
Net income (controlling interest)	$ 124.9	$ 125.4	$ 394.9	$ 374.2
Average shares outstanding (basic) (in shares)	53.1	55.8	53.9	56.3
Average shares outstanding (diluted) (in shares)	55.4	58.3	56.3	58.8
Earnings per share (basic) (in dollars per share)	$ 2.35	$ 2.25	$ 7.32	$ 6.65
Earnings per share (diluted) (in dollars per share)	2.34	2.22	7.27	6.57
Dividends per share (in dollars per share)	$ 0.3	$ 0.2	$ 0.90	$ 0.6

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 201.9	$ 216.8	$ 631.1	$ 614.9
Other comprehensive income (loss):
Foreign currency translation gain (loss)	(56.4)	53	(47.5)	92.1
Change in net realized and unrealized gain (loss) on derivative securities, net of tax	0	0.1	0.3	(0.8)
Change in net unrealized gain (loss) on investment securities, net of tax	0	(4.3)	0	(3.4)
Other comprehensive income (loss)	(56.4)	48.8	(47.2)	87.9
Comprehensive income	145.5	265.6	583.9	702.8
Comprehensive income (non-controlling interests)	(74.1)	(96.9)	(227.4)	(256.8)
Comprehensive income (controlling interest)	$ 71.4	$ 168.7	$ 356.5	$ 446

CONSOLIDATED CONDENSED BALANCE

CONSOLIDATED CONDENSED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 448.1	$ 439.5
Receivables	524.5	433.8
Fair value	144.1	77.8
Goodwill	2,648.4	2,662.5
Acquired client relationships (net)	1,357.4	1,449.7
Equity method investments in Affiliates (net)	3,055.3	3,304.7
Fixed assets (net)	104.8	111
Other investments and assets	256.2	223.1
Total assets	8,538.8	8,702.1
Liabilities and Equity
Payables and accrued liabilities	761.6	807.2
Senior debt	1,534.8	1,550.3
Convertible securities	306.6	304.4
Deferred income tax liability (net)	479.2	467.4
Other liabilities	166.5	182.4
Total liabilities	3,248.7	3,311.7
Commitments and contingencies (Note 5)
Redeemable non-controlling interests	968.9	811.9
Equity:
Common stock ($0.01 par value, 153.0 shares authorized; 58.5 shares outstanding in 2017 and 2018)	0.6	0.6
Additional paid-in capital	707.9	808.6
Accumulated other comprehensive loss	(60.1)	(21.8)
Retained earnings	4,044.1	3,698.5
Total stockholders' equity before treasury stock	4,692.5	4,485.9
Less: Treasury stock, at cost (3.4 shares in 2017 and 5.8 shares in 2018)	(1,074.3)	(663.7)
Total stockholders' equity	3,618.2	3,822.2
Non-controlling interests	703	756.3
Total equity	4,321.2	4,578.5
Total liabilities and equity	$ 8,538.8	$ 8,702.1

CONSOLIDATED CONDENSED BALANC_2

CONSOLIDATED CONDENSED BALANCE SHEETS - Parenthetical - $ / shares shares in Millions	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	153	153
Common stock, shares outstanding (in shares)	58.5	58.5
Treasury stock, at cost (in shares)	5.8	3.4

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock at Cost	Non- controlling Interests
Beginning Balance (in shares) at Dec. 31, 2016		58.5
Beginning Balance at Dec. 31, 2016	$ 4,426.5	$ 0.6	$ 1,073.5	$ (122.9)	$ 3,054.4	$ (386)	$ 806.9
Increase (Decrease) in Stockholders' Equity
Net income	614.9				374.2		240.7
Other comprehensive income	87.9			71.8			16.1
Share-based compensation	30		30
Common stock issued under share-based incentive plans	14.5		(81.8)			96.3
Share repurchases	(276.4)					(276.4)
Dividends ($0.60 per share and $0.90 per share)	(34.2)				(34.2)
Issuance costs and other	0.6		0.6
Affiliate equity activity:
Affiliate equity expense	38.6		9.4				29.2
Issuances	2.8		(0.2)				3
Repurchases	34.6		34.6
Changes in redemption value of Redeemable non-controlling interests	(216.4)		(216.4)
Transfers to Redeemable non-controlling interests	(56.8)						(56.8)
Capital contributions by Affiliate equity holders	4.5						4.5
Distributions to non-controlling interests	(266.8)						(266.8)
Ending Balance (in shares) at Sep. 30, 2017		58.5
Ending Balance at Sep. 30, 2017	$ 4,404.3	$ 0.6	849.7	(51.1)	3,394.4	(566.1)	776.8
Beginning Balance (in shares) at Dec. 31, 2017	58.5	58.5
Beginning Balance at Dec. 31, 2017	$ 4,578.5	$ 0.6	808.6	(21.8)	3,698.5	(663.7)	756.3
Increase (Decrease) in Stockholders' Equity
Net income	631.1				394.9		236.2
Other comprehensive income	(47.2)			(38.3)			(8.9)
Share-based compensation	33.5		33.5
Common stock issued under share-based incentive plans	(5.5)		(8.9)			3.4
Share repurchases	(414)					(414)
Dividends ($0.60 per share and $0.90 per share)	(49.3)				(49.3)
Affiliate equity activity:
Affiliate equity expense	43.7		10.9				32.8
Issuances	7.2		(5.4)				12.6
Repurchases	11.2		17.3				(6.1)
Changes in redemption value of Redeemable non-controlling interests	(148.1)		(148.1)
Transfers to Redeemable non-controlling interests	(30)						(30)
Capital contributions by Affiliate equity holders	3.7						3.7
Distributions to non-controlling interests	$ (293.6)						(293.6)
Ending Balance (in shares) at Sep. 30, 2018	58.5	58.5
Ending Balance at Sep. 30, 2018	$ 4,321.2	$ 0.6	$ 707.9	$ (60.1)	$ 4,044.1	$ (1,074.3)	$ 703

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - Parenthetical - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Dividends per share (in dollars per share)	$ 0.3	$ 0.2	$ 0.90	$ 0.6

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flow from (used in) operating activities:
Net income	$ 631.1	$ 614.9
Adjustments to reconcile Net income to net cash flow from operating activities:
Intangible amortization and impairments	76.5	65.1
Depreciation and other amortization	16.5	14.9
Deferred income tax provision	31.1	80.3
Equity method income (net)	(191.3)	(231.6)
Distributions of earnings received from equity method investments	410.3	368
Share-based compensation and Affiliate equity expense	77.2	68.6
Other non-cash items	(15.9)	(27.4)
Changes in assets and liabilities:
Purchases of securities by Affiliate sponsored consolidated products	(70.4)	(24.1)
Sales of securities by Affiliate sponsored consolidated products	29.6	23.2
Increase in receivables	(81.6)	(131.7)
Increase in other assets	(10.2)	(3.6)
Increase in payables, accrued liabilities and other liabilities	(26.7)	(16.1)
Cash flow from operating activities	876.2	800.5
Cash flow from (used in) investing activities:
Investments in Affiliates	(7.3)	(30.3)
Purchase of fixed assets	(13.5)	(13.9)
Purchase of investment securities	(26.8)	(22.2)
Sale of investment securities	26.7	71.3
Cash flow from (used in) investing activities	(20.9)	4.9
Cash flow from (used in) financing activities:
Borrowings of senior debt	590	445
Repayments of senior debt	(601.5)	(645)
Repurchase of common stock	(427.1)	(276.4)
Issuance of common stock	9.1	33.7
Dividends paid on common stock	(48.6)	(33.8)
Distributions to non-controlling interests	(293.6)	(266.8)
Affiliate equity issuances and repurchases	(98)	(112.5)
Other financing items	28	(15.7)
Cash flow used in financing activities	(841.7)	(871.5)
Effect of foreign currency exchange rate changes on cash and cash equivalents	(5)	10
Net increase (decrease) in cash and cash equivalents	8.6	(56.1)
Cash and cash equivalents at beginning of period	439.5	430.8
Cash and cash equivalents at end of period	$ 448.1	$ 374.7

Basis of Presentation and Use o

Basis of Presentation and Use of Estimates	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The Consolidated Financial Statements of Affiliated Managers Group, Inc. (the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for full year financial statements. In the opinion of management, all normal and recurring adjustments considered necessary for a fair statement of the Company’s interim financial position and results of operations have been included and all intercompany balances and transactions have been eliminated. In the first quarter of 2018, the Company changed its Consolidated Financial Statement presentation to present non-classified Consolidated Statements of Income and Consolidated Condensed Balance Sheets. These changes, along with other reclassifications, have been made to the prior period’s financial statements to conform to the current period’s presentation. Operating results for interim periods are not necessarily indicative of the results that may be expected for any other period or for the full year. The Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 includes additional information about its operations, financial position and accounting policies, and should be read in conjunction with this Quarterly Report on Form 10-Q. The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosures in the financial statements. Actual results could differ from those estimates. All amounts in these notes, except per share data in the text and tables herein, are stated in millions unless otherwise indicated.

Accounting Standards and Polici

Accounting Standards and Policies	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Standards and Policies	Accounting Standards and Policies Recently Adopted Accounting Standards The Company adopted several new Accounting Standard Updates (“ASUs”) in the nine months ended September 30, 2018 . While none of these ASUs had a significant impact on the Company’s Consolidated Financial Statements, the Company was required to update certain of its significant accounting policies. For a complete list of significant accounting policies, see the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017. Revenue Recognition On January 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (as amended), using a modified retrospective method and, as a result, updated its revenue recognition accounting policy as follows. Revenue primarily represents asset and performance based fees earned by the Company and its Affiliates for managing the assets of clients. Substantially all of the Company’s and its Affiliates’ contracts contain a single performance obligation, which is the provision of investment management services. Investment management services are performed and consumed simultaneously and, therefore, the Company recognizes asset based fees ratably over time. Broker-dealer and administrative fees for services that are provided and consumed over time, and which are related to Affiliate sponsored investment products, are also included ratably in revenue. Revenue recognized by the Company is adjusted for any expense reimbursement arrangements. Performance based fees, including carried interests, are recognized only upon the satisfaction of performance obligations, the resolution of any constraints (which may extend over one or more reporting periods) and when it is improbable that there will be a significant reversal in the amount of revenue recognized. As a result, any performance based fees or carried interest recognized in the current reporting period may relate to performance obligations satisfied in a previous reporting period. Revenue from investment management, broker-dealer and administrative services is typically based on the value of client assets over time, which is typically determined using observable market data. Services may be invoiced in advance or in arrears and are payable upon receipt. Any fees collected in advance are deferred and recognized as the services are performed and consumed. The Company and its Affiliates have contractual arrangements with third parties to provide distribution-related services. Fees received and expenses incurred under these arrangements are primarily based on the value of client assets over time. Distribution-related fees are presented in revenue gross of any related expenses when the Company and its Affiliates are the principal in its role as primary obligor under their distribution-related services arrangements. Distribution-related expenses are presented within Selling, general and administrative expenses in the Consolidated Statements of Income. The Company and its Affiliates may enter into contracts for which the costs to obtain or fulfill the contract are based upon a percentage of the value of a client’s future assets under management. The Company records these variable costs when incurred because they are subject to market volatility and are not estimable upon the inception of a contract with a client. Any expenses paid in advance are capitalized and amortized on a systematic basis, consistent with the transfer of services, which is the equivalent of recognizing the costs as incurred. Investments in Marketable Securities On January 1, 2018, the Company also adopted ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities, using a modified retrospective method and, as a result, updated its investments in marketable securities accounting policy as follows. Upon the adoption of ASU 2016-01, the Company no longer classifies these securities as either trading or available-for-sale securities. Realized and unrealized gains or losses on investments in marketable securities are reported within Investment and other income in the Consolidated Statements of Income. Realized gains and losses are recorded on the trade date on a specific identified basis. Derivative Financial Instruments On July 1, 2018, the Company early adopted ASU 2017-12, Derivatives and Hedging, using a modified retrospective method and, as a result, updated its derivative financial instruments accounting policy as follows. The Company and its Affiliates may utilize derivative financial instruments to offset exposure to changes in interest rates, foreign currency exchange rates and markets. The Company records derivatives in the Consolidated Condensed Balance Sheets at fair value. If the Company’s or its Affiliates’ derivative financial instruments do not qualify as cash flow, net investment or fair value hedges, changes in the fair value of the derivatives are recognized as a gain or loss in Investment and other income in the Consolidated Statements of Income. If the Company’s or its Affiliates’ derivative financial instruments qualify as cash flow or net investment hedges, the effective portion of the unrealized gain or loss is recorded in Other comprehensive income (loss) as a separate component of stockholders’ equity and reclassified to earnings with the hedged item. For cash flow hedges, hedge effectiveness is generally measured by comparing the present value of the cumulative change in the expected future cash flows of the hedged contract with the present value of the cumulative change in the expected future cash flows of the hedged item. For net investment hedges, hedge effectiveness is measured using the spot rate method. For fair value hedges, the entire change in the fair value of the hedging instrument is presented in earnings with the hedged item, unless the changes in fair value are not equal, which would result in hedge ineffectiveness. The Company assesses hedge ineffectiveness on a quarterly basis. Changes in fair value of a hedging instrument that are excluded from the assessment of hedge effectiveness, also known as excluded components, are amortized over the period of the designated hedge. Goodwill On July 1, 2018, the Company also early adopted ASU 2017-04, Goodwill and Other: Simplifying the Accounting for Goodwill Impairment, and, as a result, updated its goodwill accounting policy as follows. Goodwill represents the future economic benefits arising from assets acquired in a business combination that are not separately recognized. The Company performs a qualitative impairment test at least annually to determine if the carrying value of the reporting unit is in excess of its fair value. If a potential impairment is more likely than not, then the Company will perform a single step quantitative test with any excess of carrying value over fair value recorded as an impairment charge in Intangible amortization and impairments in the Consolidated Statements of Income. Fair Value Measurements In August 2018, the Financial Accounting Standards Board (the “FASB”) issued ASU 2018-13, Fair Value Measurements: Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement, resulting in various disclosures related to fair value measurements being eliminated, modified or supplemented. ASU 2018-13 is effective for interim and annual periods beginning after December 15, 2019, with an option to early adopt any eliminated or modified disclosures, and to delay adoption of the additional disclosures, until the effective date. On September 1, 2018, the Company early adopted the eliminated and modified disclosures of ASU 2018-13 and, as a result, updated its financial statement disclosures accordingly. A modified narrative description of measurement uncertainty for level 3 fair value measurements was applied prospectively, with all other amendments applied retrospectively. Recent Accounting Developments In February 2016, the FASB issued ASU 2016-02, Leases, and subsequently issued several related amendments. The standard requires lessees to record right-of-use assets and lease liabilities arising from most operating leases on their statement of financial position. The standard is effective for interim and annual periods beginning after December 15, 2018 for the Company and its consolidated Affiliates, and for interim and annual periods beginning after December 15, 2019 for the Company’s equity method Affiliates. The Company plans to adopt the standard using a modified retrospective method. The Company anticipates an increase in assets and liabilities on its Consolidated Condensed Balance Sheets for all lease obligations that are currently classified as operating leases, which consist primarily of real estate leases for office space, as well as additional disclosure related to its lease obligations. The Company does not expect the adoption to significantly impacted its Consolidated Statements of Income. The Company is finalizing its lease population and evaluating the discount rates used in determining the net present value of each of its lease liabilities to determine the impact of this standard on its Consolidated Condensed Balance Sheets.

Investments in Marketable Secur

Investments in Marketable Securities	9 Months Ended
	Sep. 30, 2018
Marketable Securities [Abstract]
Investments in Marketable Securities	Investments in Marketable Securities Investments in marketable securities at December 31, 2017 and September 30, 2018 were $77.8 million and $144.1 million , respectively. The following is a summary of the cost, gross unrealized gains and losses and fair value of Investments in marketable securities: December 31, September 30, Cost $ 67.1 $ 128.3 Unrealized gains 13.0 15.8 Unrealized losses (2.3 ) (0.0 ) Fair value $ 77.8 $ 144.1 In the three and nine months ended September 30, 2017 , the Company received proceeds of $23.6 million and $81.9 million , respectively, from the sale of investments in marketable securities, and recorded net gains of $9.1 million and $24.2 million , respectively. In the three and nine months ended September 30, 2018 , the Company received proceeds of $16.6 million and $42.6 million , respectively, from the sale of investments in marketable securities, and recorded net losses of $0.0 million and net gains of $4.0 million , respectively.

Investments in Affiliates and A

Investments in Affiliates and Affiliate Sponsored Investment Products	9 Months Ended
	Sep. 30, 2018
Variable Interest Entities
Investments in Affiliates and Affiliate Sponsored Investment Products	Investments in Affiliates and Affiliate Sponsored Investment Products In evaluating whether an investment must be consolidated, the Company evaluates the risk, rewards and significant terms of each of its Affiliates and other investments to determine if an investment is considered a voting rights entity (“VRE”) or a variable interest entity (“VIE”). An entity is a VRE when the total equity investment at risk is sufficient to enable the entity to finance its activities independently and when the equity holders have the obligation to absorb losses, the right to receive residual returns and the right to direct the activities of the entity that most significantly impact its economic performance. An entity is a VIE when it lacks one or more of the characteristics of a VRE, which, for the Company, are Affiliate investments structured as partnerships (or similar entities) where the limited partners lack substantive kick-out or substantive participation rights over the general partner. Assessing whether an entity is a VRE or VIE involves judgment. Upon the occurrence of certain events, management reviews and reconsiders its previous conclusion regarding the status of an entity as a VRE or a VIE. The Company consolidates VREs when it has control over significant operating, financial and investment decisions of the entity. When the Company lacks such control, but is deemed to have significant influence, the Company accounts for the entity under the equity method. Other investments in which the Company does not have rights to exercise significant influence are recorded at fair value, with changes in fair value reflected within Investment and other income. The Company consolidates VIEs when it is the primary beneficiary of the entity, which is defined as having the power to direct the activities that most significantly impact the VIE’s economic performance and the obligation to absorb losses of or the right to receive benefits from the entity that could potentially be significant to the VIE. The Company applies the equity method of accounting to VIEs where the Company is not the primary beneficiary, but has the ability to exercise significant influence over operating and financial matters of the VIE. Investments in Affiliates Substantially all of the Company’s Affiliates are considered VIEs and are either consolidated or accounted for under the equity method. A limited number of the Company’s Affiliates are considered VREs and most of these are accounted for under the equity method. When an Affiliate is consolidated, the portion of the Affiliate’s management equity owners’ earnings attributable to Owners’ Allocation is included in Net income (non-controlling interests) in the Consolidated Statements of Income. Undistributed Operating and Owners’ Allocation attributable to Affiliate management equity owners, along with their share of any tangible or intangible net assets, are presented within Non-controlling interests on the Consolidated Condensed Balance Sheets. Affiliate equity interests where the holder has certain rights to demand settlement are presented, at their current redemption values, as Redeemable non-controlling interests on the Consolidated Condensed Balance Sheets. The Company periodically issues, sells and repurchases the equity of its consolidated Affiliates. Because these transactions take place between entities that are under common control, any gains or losses attributable to these transactions are required to be included within Additional paid-in capital in the Consolidated Condensed Balance Sheets, net of any related income tax effects, in the period the transactions occur. When an Affiliate is accounted for under the equity method, the Company’s share of an Affiliate’s earnings or losses, net of amortization and impairments, is included in Equity method income (net) in the Consolidated Statements of Income and the Company’s interest in the Affiliate is reported in Equity method investments in Affiliates (net) in the Consolidated Condensed Balance Sheets. The Company’s share of income taxes incurred directly by Affiliates accounted for under the equity method is recorded within Income tax expense in the Consolidated Statements of Income. The Company periodically evaluates its equity method Affiliates for impairment. In such impairment evaluations, the Company assesses whether or not the fair value of the investment has declined below its carrying value for a period considered to be other-than-temporary. If the Company determines that a decline in fair value below the carrying value of the investment is other-than-temporary, then the carrying value of the investment is reduced to its fair value and the reduction is recorded in Equity method income (net). The unconsolidated assets, net of liabilities and non-controlling interests of equity method Affiliates considered VIEs, and the Company’s maximum risk of loss, were as follows: December 31, 2017 September 30, 2018 Unconsolidated Carrying Value and Unconsolidated Carrying Value and Affiliates accounted for under the equity method $ 1,594.4 $ 2,765.7 $ 1,169.8 $ 2,530.8 The carrying value and maximum exposure to loss of equity method Affiliates considered VREs were $539.0 million and $524.5 million as of December 31, 2017 and September 30, 2018, respectively. Affiliate Sponsored Investment Products The Company’s Affiliates sponsor various investment products where they also act as the investment advisor. These investment products are typically owned primarily by third-party investors; however, certain products are funded with general partner and seed capital investments from the Company and its Affiliates. Third-party investors in Affiliate sponsored investment products are generally entitled to substantially all of the economics of these products, except for the management and performance fees earned by the Company’s consolidated Affiliates or any gains or losses attributable to the Company’s or its consolidated Affiliates’ investments in these products. As a result, the Company does not generally consolidate these products unless the Company’s or its Affiliate’s interest in the product is considered substantial. When the Company’s or its Affiliate’s interest is considered substantial and the products are consolidated, the Company retains the specialized investment company accounting principles of the underlying products, and all of the underlying investments are carried at fair value in Investments in marketable securities, with corresponding changes in the investments’ fair values reflected in Investment and other income. Purchases and sales of securities are presented within purchases and sales by Affiliate sponsored consolidated products in the Consolidated Statements of Cash Flows. When the Company or its Affiliates no longer control these products, due to a reduction in ownership or other reasons, the products are deconsolidated with only the Company’s or its consolidated Affiliate’s investment in the product reported from the date of deconsolidation. The Company’s carrying value, and maximum exposure to loss from unconsolidated Affiliate sponsored investment products, is its or its consolidated Affiliate’s interest in the unconsolidated net assets of the respective products. The net assets of unconsolidated VIEs attributable to Affiliate sponsored investment products, and the Company’s carrying value and maximum risk of loss, were as follows: December 31, 2017 September 30, 2018 Unconsolidated VIE Net Assets Carrying Value and Maximum Exposure to Loss Unconsolidated VIE Net Assets Carrying Value and Maximum Exposure to Loss Affiliate sponsored investment products $ 2,154.6 $ 10.2 $ 2,227.3 $ 1.0

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, the Company and its Affiliates may be subject to claims, legal proceedings and other contingencies in the ordinary course of their business activities. Any such matters are subject to various uncertainties, and it is possible that some of these matters may be resolved in a manner unfavorable to the Company or its Affiliates. The Company and its Affiliates establish accruals, as necessary, for matters for which the outcome is probable and the amount of the liability can be reasonably estimated. The Company has committed to co-invest in certain Affiliate sponsored investment products. As of September 30, 2018 , these unfunded commitments were $130.4 million and may be called in future periods. As of September 30, 2018 , the Company was contingently liable, upon the achievement by certain Affiliates of specified financial targets, to make payments through 2020 related to the Company’s investments in these Affiliates. For its consolidated Affiliates, the Company was contingently liable for up to $12.7 million , and expected to make total payments of $4.5 million (of which $2.5 million are expected to be made in 2018). The present value of the total expected payments was $4.3 million . For its equity method Affiliates, the Company was contingently liable to make payments up to $150.0 million and expected to make no payments. Affiliate equity interests provide holders with a conditional right to put their interests to the Company over time. See Note 15. In addition, in connection with an investment in an equity method Affiliate, the Company entered into an arrangement with a minority owner of the Affiliate that gives such owner the right to sell a portion of its ownership interest in the Affiliate to the Company annually beginning in the fourth quarter of 2018. The purchase price of these conditional purchases will be at fair market value on the date of the transaction. The Company and certain of its consolidated Affiliates operate under regulatory authorities that require the maintenance of minimum financial or capital requirements. Management is not aware of any significant violations of such requirements.

Senior Debt

Senior Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Senior Debt	Senior Debt The Company has a $1.45 billion senior unsecured multicurrency revolving credit facility (the “revolver”). Subject to certain conditions, the Company may further increase the commitments under the revolver by up to $350.0 million . As of September 30, 2018, outstanding borrowings under the revolver were $415.0 million . The Company also has a senior unsecured term loan facility (the “term loan” and, together with the revolver, the “credit facilities”). During the nine months ended September 30, 2018, the Company amended and refinanced the term loan to adjust the interest rates and maturity date, and to convert its denomination to pound sterling. The commercial terms of the loan otherwise remained the same. As discussed further in Note 8, the Company designated the term loan as a net investment hedge. As of September 30, 2018, the term loan totaled £290.0 million , and, subject to certain conditions, could be increased by an additional £50.0 million . The revolver matures on September 30, 2020 and the term loan matures on May 31, 2021. In October 2018, the Company further amended the term loan to convert its denomination from pound sterling to U.S. dollars, which is further described in Note 19.

Convertible Securities

Convertible Securities	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Convertible Securities	Convertible Securities As of September 30, 2018, the Company had 5.15% junior convertible trust preferred securities outstanding (the “junior convertible securities”). Effective August 10, 2018 and in accordance with the convertible securities indenture, the Company adjusted the conversion rate of the junior convertible securities from 0.2500 shares of common stock to 0.2525 shares of common stock per $50.00 junior convertible security, equivalent to an adjusted conversion price of $ 198.02 per share of common stock. The adjustment was the result of the Company’s cumulative declared dividends on its common stock since the initiation of its dividend through August 2018.

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company and its Affiliates may use derivative financial instruments to offset exposure to changes in interest rates, foreign currency exchange rates and markets. On August 28, 2018, the Company entered into a pound sterling-denominated forward foreign currency contract (the “forward contract”) with a large financial institution (the “counterparty”) to deliver £285.8 million for $400.0 million in 2024. Concurrent with entering into the forward contract, the Company entered into a collar contract (the “collar contract”) with the same counterparty, for the same notional amounts and expiration date as the forward contract, through the sale of a put option with a lower strike price of 1.288 U.S. dollars per one pound sterling and the purchase of a call option with an upper strike price of 1.535 U.S. dollars per one pound sterling. The forward contract and the collar contract were designated as net investment hedges against fluctuations in exchange rates on certain of the Company’s investments in Affiliates with the pound sterling as their functional currency. The forward contract’s excluded component is recognized in earnings on a straight-line basis over the respective period of the forward contract as a reduction to Interest expense in the Consolidated Statements of Income. All other changes in the fair values of the forward contract and the collar contract are reported in Foreign currency translation gain (loss) in the Consolidated Statements of Comprehensive Income. The Company assesses hedge ineffectiveness on a quarterly basis. Any hedge ineffectiveness is recorded in Investment and other income in the Consolidated Statements of Income. For the three and nine months ended September 30, 2018 , there was no ineffectiveness recorded. The Company’s Affiliates use forward foreign currency contracts to hedge the risk of foreign exchange rate movements, none of which were significant. The following table summarizes the Company’s and its Affiliates’ derivative financial instruments measured at fair value on a recurring basis. As of December 31, 2017, the Company and its Affiliates did not have any significant derivative financial instruments. September 30, 2018 Assets (1) Liabilities (2) Forward contracts $ 1.0 $ 6.4 Put option — 21.6 Call option — (23.5 ) Total $ 1.0 $ 4.5 (1) Amounts are presented in Other investments and assets in the Consolidated Condensed Balance Sheets. (2) Amounts are presented in Other liabilities in the Consolidated Condensed Balance Sheets. The following table summarizes the effect of the derivative financial instruments on the Consolidated Statements of Comprehensive Income and the Consolidated Statements of Income. In the three and nine months ended September 30, 2017, the Company and its Affiliates did not have any significant derivative financial instruments. For the Three Months Ended September 30, 2018 For the Nine Months Ended September 30, 2018 Gain (Loss) Recognized in Other Comprehensive Income Gain (Loss) Recognized in Earnings from Excluded Components (1) Gain (Loss) Recognized in Other Comprehensive Income Gain (Loss) Recognized in Earnings from Excluded Components (1) Forward contracts $ (5.9 ) $ 0.5 $ (5.6 ) $ 0.5 Put option 1.6 — 1.6 — Call option 0.3 — 0.3 — Total $ (4.0 ) $ 0.5 $ (3.7 ) $ 0.5 (1) The excluded components are recorded as a reduction in Interest expense. In the three and nine months ended September 30, 2018 , the Company and its Affiliates did not have any significant gains (losses) reclassified from Accumulated other comprehensive income into earnings. The terms of the Company’s forward contract and collar contract require the Company and the counterparty to post cash collateral in certain circumstances throughout the duration of the contracts. As of September 30, 2018 , the Company held $3.1 million of cash collateral from the counterpary. The counterparty to the Company’s derivative contracts is a large financial institution. The derivative contracts are governed by an International Swaps and Derivative Association (“ISDA”) Master Agreement with the counterparty, which provides for settlement netting and close-out netting between the Company and the counterparty, which are legally enforceable rights to setoff. The Company also actively monitors its counterparty credit risk related to derivative financial instruments. The Company’s derivative contracts include provisions to protect against counterparty rating downgrades, which in certain cases may result in the counterparty posting additional collateral to the Company, or give rise to a termination right. The Company considers set-off rights and counterparty credit risk in the valuation of its positions, and recognizes a credit valuation adjustment as appropriate. In October 2018, the Company entered into an additional pound sterling-denominated forward foreign currency contract and an additional collar contract, which are further described in Note 19.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following tables summarize the Company’s financial assets and liabilities that are measured at fair value on a recurring basis: Fair Value Measurements December 31, Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets Cash equivalents $ 40.4 $ 40.4 $ — $ — Investments in marketable securities 77.8 77.8 — — Derivative financial instruments (1) 0.2 — 0.2 — Financial Liabilities (2) Contingent payment arrangements $ 9.4 $ — $ — $ 9.4 Affiliate equity repurchase obligations 49.2 — — 49.2 Derivative financial instruments 0.6 — 0.6 — Fair Value Measurements September 30, Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets Cash equivalents $ 48.1 $ 48.1 $ — $ — Investments in marketable securities 144.1 144.1 — — Derivative financial instruments (1) 1.0 — 1.0 — Financial Liabilities (2) Contingent payment arrangements $ 4.3 $ — $ — $ 4.3 Affiliate equity repurchase obligations 28.7 — — 28.7 Derivative financial instruments 4.5 — 4.5 — __________________________ (1) Amounts are presented within Other investments and assets. (2) Amounts are presented within Other liabilities. Level 3 Financial Assets and Liabilities The following tables present the changes in level 3 liabilities: For the Three Months Ended September 30, 2017 2018 Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Balance, beginning of period $ 7.8 $ 70.7 $ 4.2 $ 36.9 Net realized and unrealized (gains) losses (1) 0.3 (0.2 ) 0.1 — Purchases and issuances (2) — 11.1 — 40.1 Settlements and reductions — (35.9 ) — (48.3 ) Balance, end of period $ 8.1 $ 45.7 $ 4.3 $ 28.7 Net change in unrealized (gains) losses relating to instruments still held at the reporting date (1) $ 0.3 $ — $ 0.1 $ — For the Nine Months Ended September 30, 2017 2018 Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Balance, beginning of period $ 8.6 $ 12.1 $ 9.4 $ 49.2 Net realized and unrealized (gains) losses (1) 2.3 (0.2 ) (0.3 ) — Purchases and issuances (2) — 161.5 — 86.0 Settlements and reductions (2.8 ) (127.7 ) (4.8 ) (106.5 ) Balance, end of period $ 8.1 $ 45.7 $ 4.3 $ 28.7 Net change in unrealized (gains) losses relating to instruments still held at the reporting date (1) $ 2.3 $ — $ 0.4 $ — ___________________________ (1) Accretion and changes in the expected value of the Company’s contingent payment arrangements and Affiliate equity repurchase obligations are recorded in Other expenses (net) in the Consolidated Statements of Income. (2) Includes transfers from Redeemable non-controlling interests. The following table presents certain quantitative information about the significant unobservable inputs used in valuing the Company’s level 3 fair value measurements: Quantitative Information About Level 3 Fair Value Measurements Valuation Techniques Unobservable Input Fair Value at Range at Fair Value at September 30, 2018 Range at September 30, 2018 Contingent payment arrangements Discounted cash flow Growth rates $ 9.4 7% - 8% $ 4.3 7% Discount rates 15% - 16% 15% Affiliate equity repurchase obligations Discounted cash flow Growth rates 49.2 0% - 11% 28.7 4% - 9% Discount rates 12% - 16% 14% - 16% Contingent payment arrangements represent the present value of the expected future settlement of contingent payment arrangements related to the Company’s investments in consolidated Affiliates. As of September 30, 2018, there were no changes to growth rates or discount rates that had a significant impact to contingent payment arrangements. Affiliate equity repurchase obligations include agreements to repurchase Affiliate equity. As of September 30, 2018, there were no changes to growth or discount rates that had a significant impact to Affiliate equity repurchase obligations recorded in prior periods. Investments Measured at NAV as a Practical Expedient The Company’s Affiliates sponsor investment products in which the Company and its Affiliates may make general partner and seed capital investments. The Company uses the net asset value (“NAV”) of these investments as a practical expedient for their fair value and reports these products within Other investments and assets. The following table summarizes the nature of the Company’s investments, unfunded commitments and any related liquidity restrictions or other factors that may impact the ultimate value realized: December 31, 2017 September 30, 2018 Category of Investment Fair Value Unfunded Commitments Fair Value Unfunded Commitments Private equity funds (1) $ 156.1 $ 98.8 $ 185.4 $ 130.4 Other funds (2) 8.9 — 7.4 — Other investments (3) $ 165.0 $ 98.8 $ 192.8 $ 130.4 ___________________________ (1) The Company uses NAV as a practical expedient one quarter in arrears (adjusted for current period calls and distributions) to determine the fair value. These funds primarily invest in a broad range of private equity funds, as well as making direct investments. Distributions will be received as the underlying assets are liquidated over the life of the funds, which is generally up to 15 years . (2) These are multi-disciplinary funds that invest across various asset classes and strategies, including long/short equity, credit and real estate. Investments are generally redeemable on a daily, monthly or quarterly basis. (3) Fair value attributable to the controlling interest was $80.1 million and $115.0 million as of December 31, 2017 and September 30, 2018 , respectively. Other Financial Assets and Liabilities Not Carried at Fair Value The carrying amount of Receivables and Payables and accrued liabilities, which is reported in the Consolidated Condensed Balance Sheets, approximates fair value because of the short-term nature of these instruments. The carrying value of notes receivable, which is reported in Other investments and assets, approximates fair value because interest rates and other terms are at market rates. The carrying value of the credit facilities, which is reported in Senior debt in the Consolidated Condensed Balance Sheets, approximates fair value because the credit facilities have variable interest based on selected short-term rates. The following table summarizes the Company’s other financial liabilities not carried at fair value: December 31, 2017 September 30, 2018 Carrying Value Fair Value Carrying Value Fair Value Fair Value Hierarchy Senior notes (1) $ 745.7 $ 765.2 $ 746.1 $ 743.8 Level 2 Convertible securities 309.9 549.8 311.8 498.7 Level 2 ___________________________ (1) The carrying value of the senior notes is reported in Senior debt.

Goodwill and Acquired Client Re

Goodwill and Acquired Client Relationships	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Acquired Client Relationships	Goodwill and Acquired Client Relationships The following tables present the changes in the Company’s consolidated Affiliates’ Goodwill and components of Acquired client relationships (net) in the Consolidated Condensed Balance Sheets: Goodwill Balance, as of December 31, 2017 $ 2,662.5 Foreign currency translation (14.1 ) Balance, as of September 30, 2018 $ 2,648.4 As of September 30, 2018, the Company completed its impairment assessment on its goodwill and no impairment was indicated. Acquired Client Relationships (Net) Definite-lived Indefinite-lived Total Gross Book Value Accumulated Amortization Net Book Value Net Book Value Net Book Value Balance, as of December 31, 2017 $ 1,295.5 $ (874.5 ) $ 421.0 $ 1,028.7 $ 1,449.7 Intangible amortization and impairments — (76.5 ) (76.5 ) — (76.5 ) Foreign currency translation (1.9 ) — (1.9 ) (13.9 ) (15.8 ) Balance, as of September 30, 2018 $ 1,293.6 $ (951.0 ) $ 342.6 $ 1,014.8 $ 1,357.4 Definite-lived acquired client relationships are amortized over their expected period of economic benefit. The Company recorded amortization expense within Intangible amortization and impairments in the Consolidated Statements of Income for these relationships of $21.2 million and $65.1 million for the three and nine months ended September 30, 2017 , respectively, and $30.1 million and $76.5 million for the three and nine months ended September 30, 2018 , respectively. Based on relationships existing as of September 30, 2018 , the Company estimates that its consolidated annual amortization expense will be approximately $100 million in 2018, approximately $90 million in 2019, approximately $60 million in 2020 and approximately $35 million in each of 2021 and 2022.

Equity Method Investments in Af

Equity Method Investments in Affiliates	9 Months Ended
	Sep. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments in Affiliates	Equity Method Investments in Affiliates The following table presents the change in Equity method investments in Affiliates (net): Equity Method Investments in Affiliates (Net) Balance, as of December 31, 2017 $ 3,304.7 Equity method earnings 300.3 Equity method intangible amortization and impairments (109.0 ) Distributions of earnings from equity method investments (410.3 ) Foreign currency translation (21.3 ) Other (9.1 ) Balance, as of September 30, 2018 $ 3,055.3 Definite-lived acquired relationships at the Company’s equity method Affiliates are amortized over their expected period of economic benefit. The Company recognized amortization expense for these relationships of $25.9 million and $71.7 million for the three and nine months ended September 30, 2017 , respectively, and $22.2 million and $109.0 million for the three and nine months ended September 30, 2018 , respectively. Based on relationships existing as of September 30, 2018 , the Company estimates the annual amortization expense attributable to its equity method Affiliates will be approximately $100 million in 2018 and approximately $90 million in each of 2019, 2020, 2021 and 2022. In the second quarter of 2018, the Company recognized a $33.3 million expense ( $25.0 million net of tax), which together with an expense recorded in the fourth quarter of 2017, reduced the carrying value of the Company’s investment in the Affiliate to zero . The Company has determined that one of its equity method Affiliates is significant under Rule 10-01(b)(1) of Regulation S-X. For the three and nine months ended September 30, 2017 , this equity method Affiliate recognized revenue of $301.8 million and $826.6 million , respectively, and net income of $178.3 million and $471.3 million , respectively. For the three and nine months ended September 30, 2018 , this equity method Affiliate recognized revenue of $ 283.2 million and $ 884.9 million, respectively, and net income of $ 135.0 million and $ 443.3 million, respectively.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions A prior owner of one of the Company’s consolidated Affiliates retained interests in certain of the Affiliate’s private equity investment partnerships. The prior owner’s interests are presented in Other liabilities and were $61.2 million and $51.7 million at December 31, 2017 and September 30, 2018 , respectively. The Company and its Affiliates earn asset and performance based fees and incur distribution and other expenses for services provided to Affiliate sponsored investment products. In addition, Affiliate management owners and Company officers may serve as trustees or directors of certain investment vehicles from which an Affiliate earns fees. The Company had liabilities to related parties for contingent payment arrangements in connection with certain business combinations. The net present value of the total amounts payable were $9.4 million and $4.3 million as of December 31, 2017 and September 30, 2018 , respectively, and were included in Other liabilities. The Company has related party transactions in association with its Affiliate equity transactions, as more fully described in Notes 14 and 15.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation The following table presents share-based compensation expense: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Share-based compensation $ 10.3 $ 11.7 $ 30.0 $ 33.5 Tax benefit 4.0 2.9 11.5 8.4 As of December 31, 2017, the Company had unrecognized share-based compensation expense of $63.5 million . As of September 30, 2018 , the Company had unrecognized share-based compensation expense of $67.1 million , which will be recognized over a weighted average period of approximately two years (assuming no forfeitures). Stock Options The following table summarizes transactions in the Company’s stock options: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (Years) Unexercised options outstanding - December 31, 2017 0.6 $ 122.04 Options granted 0.0 179.54 Options exercised (0.1 ) 100.00 Options forfeited (0.0) 122.40 Unexercised options outstanding - September 30, 2018 0.5 130.30 4.0 Exercisable at September 30, 2018 0.1 136.33 2.7 For the nine months ended September 30, 2017 and 2018, the Company granted stock options with fair values of $0.8 million and $1.0 million , respectively. Stock options generally vest over a period of three to four years and expire seven years after the grant date. All options have been granted with exercise prices equal to the closing price of the Company’s common stock on the grant date. In certain circumstances, option awards also require certain performance conditions to be satisfied in order for the options to be exercised. The fair value of options granted was estimated using the Black-Scholes option pricing model and were $48.05 and $48.64 , per option, for the nine months ended September 30, 2017 and 2018, respectively. The weighted average grant date assumptions used to estimate the fair value of options granted were as follows: For the Nine Months Ended September 30, 2017 2018 Dividend yield 0.5 % 0.8 % Expected volatility 28.0 % 25.5 % Risk-free interest rate 2.1 % 2.8 % Expected life of options (in years) 5.7 5.7 Forfeiture rate — % — % Restricted Stock The following table summarizes transactions in the Company’s restricted stock units: Restricted Stock Units Weighted Average Grant Date Value Unvested units - December 31, 2017 0.4 $ 162.32 Units granted 0.2 201.76 Units vested (0.0) 198.24 Units forfeited (0.0) 152.09 Unvested units - September 30, 2018 0.6 172.58 For the nine months ended September 30, 2017 and 2018, the Company granted restricted stock unit awards with fair values of $36.7 million and $37.7 million , respectively. These awards were valued based on the closing price of the Company’s common stock on the grant date and the number of awards expected to be delivered. Awards containing vesting conditions generally require service over a period of three to four years and may also require the satisfaction of certain performance conditions.

Redeemable Non-Controlling Inte

Redeemable Non-Controlling Interests	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
Redeemable Non-Controlling Interests	Redeemable Non-Controlling Interests Affiliate equity interests provide holders with an equity interest in one of the Company’s Affiliates, consistent with the structured partnership interests in place at the respective Affiliate. Affiliate equity holders generally have a conditional right to put their interests to the Company at certain intervals (between five and 15 years from the date the equity interest is received or on an annual basis following an Affiliate equity holder’s departure). The current redemption value of the Company’s Affiliate equity interests is presented as Redeemable non-controlling interests. Changes in the current redemption value are recorded to Additional paid-in capital. When the Company has an unconditional obligation to repurchase Affiliate equity interests, they are reclassified to Other liabilities. The following table presents the changes in Redeemable non-controlling interests: Redeemable Non-controlling interests Balance, as of December 31, 2017 $ 811.9 Changes attributable to consolidated products 64.9 Transfers to Other liabilities (86.0 ) Transfers from Non-controlling interests 30.0 Changes in redemption value 148.1 Balance, as of September 30, 2018 $ 968.9

Affiliate Equity

Affiliate Equity	9 Months Ended
	Sep. 30, 2018
Affiliate Equity [Abstract]
Affiliate Equity	Affiliate Equity Affiliate equity interests are allocated income in a manner that is consistent with the structured partnership interests in place at the respective Affiliate. The Company’s Affiliates generally pay quarterly distributions to Affiliate equity holders. For the nine months ended September 30, 2017 and 2018, distributions paid to Affiliate equity holders (non-controlling interests) were $266.8 million and $293.6 million , respectively. The Company periodically repurchases Affiliate equity interests from and issues Affiliate equity interests to its Affiliate partners, its employees and its officers. For the nine months ended September 30, 2017 and 2018, the amount of cash paid for repurchases was $121.3 million and $104.3 million , respectively. For the nine months ended September 30, 2017 and 2018, the total amount of cash received for issuances was $8.8 million and $6.3 million , respectively. Sales and repurchases of Affiliate equity generally occur at fair value; however, the Company also grants Affiliate equity to its Affiliate partners, its employees and its officers as a form of compensation. If the equity is issued for consideration below the fair value of the equity, or repurchased for consideration above the fair value of the equity, the difference is recorded as compensation expense in Compensation and related expenses in the Consolidated Statements of Income over the requisite service period. The following table presents Affiliate equity expense: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Controlling interest $ 2.3 $ 6.1 $ 9.4 $ 10.9 Non-controlling interests 7.7 9.9 29.2 32.8 Total $ 10.0 $ 16.0 $ 38.6 $ 43.7 The following table presents unrecognized Affiliate equity expense: Controlling Interest Remaining Life Non-controlling Interests Remaining Life December 31, 2017 $ 33.3 5 years $ 95.9 6 years September 30, 2018 36.8 5 years 120.0 6 years The Company records amounts receivable from and payable to Affiliate equity holders in connection with the transfer of Affiliate equity interests that have not settled at the end of the period. The total receivable was $12.4 million and $17.8 million at December 31, 2017 and September 30, 2018 , respectively, and was included in Other investments and assets. The total payable was $49.2 million and $28.7 million as of December 31, 2017 and September 30, 2018 , respectively, and was included in Other liabilities. Effects of Changes in the Company’s Ownership in Affiliates The Company periodically acquires interests from, and transfers interests to, Affiliate equity holders. Because these transactions do not result in a change of control, any gain or loss related to these transactions is recorded to Additional paid-in capital, which increases or decreases the controlling interest’s equity. No gain or loss related to these transactions is recognized in the Consolidated Statements of Income or the Consolidated Statements of Comprehensive Income. While the Company presents the current redemption value of Affiliate equity within Redeemable non-controlling interests, with changes in the current redemption value increasing or decreasing the controlling interest’s equity over time, the following table presents the cumulative effect that ownership changes had on the controlling interest’s equity related only to Affiliate equity transactions that settled during the applicable periods: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Net income (controlling interest) $ 125.4 $ 124.9 $ 374.2 $ 394.9 Decrease in controlling interest paid-in capital from Affiliate equity issuances (0.3 ) (0.5 ) (0.6 ) (3.8 ) Decrease in controlling interest paid-in capital from Affiliate equity repurchases (12.7 ) (31.7 ) (81.8 ) (63.8 ) Net income (controlling interest) including the net impact of Affiliate equity transactions $ 112.4 $ 92.7 $ 291.8 $ 327.3

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, changes in U.S. tax laws were enacted which significantly revised U.S. corporate income tax by, among other things, lowering the corporate income tax rate, implementing a modified territorial tax system, and imposing a one-time transition tax on deemed repatriated foreign earnings and profits. In 2017, the Company recorded a provisional one-time net benefit of $194.1 million as a reasonable estimate of the impact of the changes in U.S. tax laws. For the nine months ended September 30, 2018 , the Company did no t record any significant changes to its provisional amount. The impact of the changes in U.S. tax laws may be refined as further guidance, interpretations or information becomes available, upon completion by the Company of its evaluation of the impact of the changes in U.S. tax laws or upon the Company’s election of a policy with respect to the deferred tax effects of the Global Intangible Low Tax Income provisions of U.S. tax laws. The Company will finalize its accounting for the impact of changes in the U.S. tax laws in the fourth quarter of 2018. The Company’s consolidated income tax provision includes taxes attributable to the controlling interest and, to a lesser extent, taxes attributable to the non-controlling interests. The following table presents the consolidated provision for income taxes: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Controlling interest: Current tax $ 39.6 $ 33.8 $ 102.0 $ 107.4 Intangible-related deferred taxes 22.9 12.2 61.8 30.1 Other deferred taxes 1.6 0.2 18.7 1.2 Total controlling interest 64.1 46.2 182.5 138.7 Non-controlling interests: Current tax $ 2.1 $ 2.4 $ 5.9 $ 7.6 Deferred taxes (0.1 ) (0.1 ) (0.2 ) (0.2 ) Total non-controlling interests 2.0 2.3 5.7 7.4 Provision for income taxes $ 66.1 $ 48.5 $ 188.2 $ 146.1 Income before income taxes (controlling interest) $ 189.5 $ 171.1 $ 556.7 $ 533.6 Effective tax rate (controlling interest) (1) 33.8 % 27.0 % 32.8 % 26.0 % __________________________ (1) Taxes attributable to the controlling interest divided by Income before income taxes (controlling interest).

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The calculation of Earnings per share (basic) is based on the weighted average number of shares of the Company’s common stock outstanding during the period. Earnings per share (diluted) is similar to Earnings per share (basic), but adjusts for the dilutive effect of the potential issuance of incremental shares of the Company’s common stock. The following is a reconciliation of the numerator and denominator used in the calculation of basic and diluted earnings per share available to common stockholders: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Numerator Net income (controlling interest) $ 125.4 $ 124.9 $ 374.2 $ 394.9 Interest expense on convertible securities, net of taxes 3.9 4.7 11.6 14.2 Net income (controlling interest), as adjusted $ 129.3 $ 129.6 $ 385.8 $ 409.1 Denominator Average shares outstanding (basic) 55.8 53.1 56.3 53.9 Effect of dilutive instruments: Stock options and restricted stock units 0.3 0.1 0.3 0.2 Convertible securities 2.2 2.2 2.2 2.2 Average shares outstanding (diluted) 58.3 55.4 58.8 56.3 Average shares outstanding (diluted) in the table above excludes share-based awards that have not satisfied performance conditions and the anti-dilutive effect of the following: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Stock options and restricted stock units 0.0 0.2 0.1 0.2 The Company may settle portions of its Affiliate equity purchases in shares of its common stock. Because it is the Company’s intention to settle these potential purchases in cash, the calculation of Average shares outstanding (diluted) excludes any potential dilutive effect from possible share settlements of Affiliate equity purchases. In the three and nine months ended September 30, 2018 , the Company repurchased 0.8 million and 2.5 million shares, respectively, of its common stock at an average price per share of $ 146.85 and $166.19 , respectively.

Comprehensive Income

Comprehensive Income	9 Months Ended
	Sep. 30, 2018
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Comprehensive Income	Comprehensive Income The following tables present the tax effects allocated to each component of Other comprehensive income (loss): For the Three Months Ended September 30, 2017 2018 Pre-Tax Tax Benefit Net of Tax Pre-Tax Tax Benefit Net of Tax Foreign currency translation adjustment $ 53.0 $ — $ 53.0 $ (56.0 ) $ (0.4 ) $ (56.4 ) Change in net realized and unrealized gain (loss) on derivative securities 0.2 (0.1 ) 0.1 (0.0 ) — (0.0 ) Change in net unrealized gain (loss) on investment securities (6.8 ) 2.5 (4.3 ) — — — Other comprehensive income (loss) $ 46.4 $ 2.4 $ 48.8 $ (56.0 ) $ (0.4 ) $ (56.4 ) For the Nine Months Ended September 30, 2017 2018 Pre-Tax Tax Benefit Net of Tax Pre-Tax Tax Benefit Net of Tax Foreign currency translation adjustment $ 92.1 $ — $ 92.1 $ (47.1 ) $ (0.4 ) $ (47.5 ) Change in net realized and unrealized gain (loss) on derivative securities (0.7 ) (0.1 ) (0.8 ) 0.3 — 0.3 Change in net unrealized gain on investment securities (6.6 ) 3.2 (3.4 ) — — — Other comprehensive income (loss) $ 84.8 $ 3.1 $ 87.9 $ (46.8 ) $ (0.4 ) $ (47.2 ) The components of accumulated other comprehensive income (loss), net of taxes, were as follows: Foreign Currency Translation Adjustment Realized and Unrealized Gains (Losses) on Derivative Securities Unrealized Gains (Losses) on Investment Securities (1) Total Balance, as of December 31, 2017 $ (85.9 ) $ (0.4 ) $ 2.1 $ (84.2 ) Other comprehensive income before reclassifications (47.5 ) (0.0) — (47.5 ) Amounts reclassified — 0.3 (2.1 ) (1.8 ) Net other comprehensive income (loss) (47.5 ) 0.3 (2.1 ) (49.3 ) Balance, as of September 30, 2018 $ (133.4 ) $ (0.1 ) $ — $ (133.5 ) __________________________ (1) In connection with the Company’s adoption of ASU 2016-01, the unrealized losses on investment securities, which related to the non-controlling interests, were reclassified to Non-controlling interests.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In October 2018, the Company amended its senior unsecured term loan facility to convert its denomination from pound sterling to U.S. dollars and to increase the borrowings to $450.0 million , with the ability to borrow an additional $75.0 million , subject to certain conditions. The Company pays interest on any outstanding obligations under the term loan at specified rates, based either on the U.S. dollar LIBOR rate or the prime rate as in effect from time to time. The other commercial terms of the term loan, including maturity date, remained the same. In connection with the conversion, the Company de-designated the term loan as a net investment hedge. In October 2018, the Company entered into a pound sterling-denominated forward foreign currency contract to deliver £325.3 million for $450.0 million in 2021 and a collar contract with the same counterparty, for the same notional amounts and expiration date as the forward contract, through the sale of a put option with a lower strike price of 1.318 U.S. dollars per one pound sterling and the purchase of a call option with an upper strike price of 1.448 U.S. dollars per one pound sterling. The forward contracts and the collar contracts provide net settlement rights. The forward contract and the collar contract were designated as net investment hedges against fluctuations in exchange rates on certain of the Company’s investments in Affiliates with the pound sterling as their functional currency.

Accounting Standards and Poli_2

Accounting Standards and Policies (Policies)	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Basis of Presentation	The Consolidated Financial Statements of Affiliated Managers Group, Inc. (the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for full year financial statements. In the opinion of management, all normal and recurring adjustments considered necessary for a fair statement of the Company’s interim financial position and results of operations have been included and all intercompany balances and transactions have been eliminated. In the first quarter of 2018, the Company changed its Consolidated Financial Statement presentation to present non-classified Consolidated Statements of Income and Consolidated Condensed Balance Sheets. These changes, along with other reclassifications, have been made to the prior period’s financial statements to conform to the current period’s presentation. Operating results for interim periods are not necessarily indicative of the results that may be expected for any other period or for the full year. The Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 includes additional information about its operations, financial position and accounting policies, and should be read in conjunction with this Quarterly Report on Form 10-Q. All amounts in these notes, except per share data in the text and tables herein, are stated in millions unless otherwise indicated
Use of Estimates	The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosures in the financial statements. Actual results could differ from those estimates.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards The Company adopted several new Accounting Standard Updates (“ASUs”) in the nine months ended September 30, 2018 . While none of these ASUs had a significant impact on the Company’s Consolidated Financial Statements, the Company was required to update certain of its significant accounting policies. For a complete list of significant accounting policies, see the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017. Revenue Recognition On January 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (as amended), using a modified retrospective method and, as a result, updated its revenue recognition accounting policy as follows. Revenue primarily represents asset and performance based fees earned by the Company and its Affiliates for managing the assets of clients. Substantially all of the Company’s and its Affiliates’ contracts contain a single performance obligation, which is the provision of investment management services. Investment management services are performed and consumed simultaneously and, therefore, the Company recognizes asset based fees ratably over time. Broker-dealer and administrative fees for services that are provided and consumed over time, and which are related to Affiliate sponsored investment products, are also included ratably in revenue. Revenue recognized by the Company is adjusted for any expense reimbursement arrangements. Performance based fees, including carried interests, are recognized only upon the satisfaction of performance obligations, the resolution of any constraints (which may extend over one or more reporting periods) and when it is improbable that there will be a significant reversal in the amount of revenue recognized. As a result, any performance based fees or carried interest recognized in the current reporting period may relate to performance obligations satisfied in a previous reporting period. Revenue from investment management, broker-dealer and administrative services is typically based on the value of client assets over time, which is typically determined using observable market data. Services may be invoiced in advance or in arrears and are payable upon receipt. Any fees collected in advance are deferred and recognized as the services are performed and consumed. The Company and its Affiliates have contractual arrangements with third parties to provide distribution-related services. Fees received and expenses incurred under these arrangements are primarily based on the value of client assets over time. Distribution-related fees are presented in revenue gross of any related expenses when the Company and its Affiliates are the principal in its role as primary obligor under their distribution-related services arrangements. Distribution-related expenses are presented within Selling, general and administrative expenses in the Consolidated Statements of Income. The Company and its Affiliates may enter into contracts for which the costs to obtain or fulfill the contract are based upon a percentage of the value of a client’s future assets under management. The Company records these variable costs when incurred because they are subject to market volatility and are not estimable upon the inception of a contract with a client. Any expenses paid in advance are capitalized and amortized on a systematic basis, consistent with the transfer of services, which is the equivalent of recognizing the costs as incurred. Investments in Marketable Securities On January 1, 2018, the Company also adopted ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities, using a modified retrospective method and, as a result, updated its investments in marketable securities accounting policy as follows. Upon the adoption of ASU 2016-01, the Company no longer classifies these securities as either trading or available-for-sale securities. Realized and unrealized gains or losses on investments in marketable securities are reported within Investment and other income in the Consolidated Statements of Income. Realized gains and losses are recorded on the trade date on a specific identified basis. Derivative Financial Instruments On July 1, 2018, the Company early adopted ASU 2017-12, Derivatives and Hedging, using a modified retrospective method and, as a result, updated its derivative financial instruments accounting policy as follows. The Company and its Affiliates may utilize derivative financial instruments to offset exposure to changes in interest rates, foreign currency exchange rates and markets. The Company records derivatives in the Consolidated Condensed Balance Sheets at fair value. If the Company’s or its Affiliates’ derivative financial instruments do not qualify as cash flow, net investment or fair value hedges, changes in the fair value of the derivatives are recognized as a gain or loss in Investment and other income in the Consolidated Statements of Income. If the Company’s or its Affiliates’ derivative financial instruments qualify as cash flow or net investment hedges, the effective portion of the unrealized gain or loss is recorded in Other comprehensive income (loss) as a separate component of stockholders’ equity and reclassified to earnings with the hedged item. For cash flow hedges, hedge effectiveness is generally measured by comparing the present value of the cumulative change in the expected future cash flows of the hedged contract with the present value of the cumulative change in the expected future cash flows of the hedged item. For net investment hedges, hedge effectiveness is measured using the spot rate method. For fair value hedges, the entire change in the fair value of the hedging instrument is presented in earnings with the hedged item, unless the changes in fair value are not equal, which would result in hedge ineffectiveness. The Company assesses hedge ineffectiveness on a quarterly basis. Changes in fair value of a hedging instrument that are excluded from the assessment of hedge effectiveness, also known as excluded components, are amortized over the period of the designated hedge. Goodwill On July 1, 2018, the Company also early adopted ASU 2017-04, Goodwill and Other: Simplifying the Accounting for Goodwill Impairment, and, as a result, updated its goodwill accounting policy as follows. Goodwill represents the future economic benefits arising from assets acquired in a business combination that are not separately recognized. The Company performs a qualitative impairment test at least annually to determine if the carrying value of the reporting unit is in excess of its fair value. If a potential impairment is more likely than not, then the Company will perform a single step quantitative test with any excess of carrying value over fair value recorded as an impairment charge in Intangible amortization and impairments in the Consolidated Statements of Income. Fair Value Measurements In August 2018, the Financial Accounting Standards Board (the “FASB”) issued ASU 2018-13, Fair Value Measurements: Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement, resulting in various disclosures related to fair value measurements being eliminated, modified or supplemented. ASU 2018-13 is effective for interim and annual periods beginning after December 15, 2019, with an option to early adopt any eliminated or modified disclosures, and to delay adoption of the additional disclosures, until the effective date. On September 1, 2018, the Company early adopted the eliminated and modified disclosures of ASU 2018-13 and, as a result, updated its financial statement disclosures accordingly. A modified narrative description of measurement uncertainty for level 3 fair value measurements was applied prospectively, with all other amendments applied retrospectively. Recent Accounting Developments In February 2016, the FASB issued ASU 2016-02, Leases, and subsequently issued several related amendments. The standard requires lessees to record right-of-use assets and lease liabilities arising from most operating leases on their statement of financial position. The standard is effective for interim and annual periods beginning after December 15, 2018 for the Company and its consolidated Affiliates, and for interim and annual periods beginning after December 15, 2019 for the Company’s equity method Affiliates. The Company plans to adopt the standard using a modified retrospective method. The Company anticipates an increase in assets and liabilities on its Consolidated Condensed Balance Sheets for all lease obligations that are currently classified as operating leases, which consist primarily of real estate leases for office space, as well as additional disclosure related to its lease obligations. The Company does not expect the adoption to significantly impacted its Consolidated Statements of Income. The Company is finalizing its lease population and evaluating the discount rates used in determining the net present value of each of its lease liabilities to determine the impact of this standard on its Consolidated Condensed Balance Sheets.
Investments in Affiliates and Affiliate Sponsored Investments Products	Investments in Affiliates and Affiliate Sponsored Investment Products In evaluating whether an investment must be consolidated, the Company evaluates the risk, rewards and significant terms of each of its Affiliates and other investments to determine if an investment is considered a voting rights entity (“VRE”) or a variable interest entity (“VIE”). An entity is a VRE when the total equity investment at risk is sufficient to enable the entity to finance its activities independently and when the equity holders have the obligation to absorb losses, the right to receive residual returns and the right to direct the activities of the entity that most significantly impact its economic performance. An entity is a VIE when it lacks one or more of the characteristics of a VRE, which, for the Company, are Affiliate investments structured as partnerships (or similar entities) where the limited partners lack substantive kick-out or substantive participation rights over the general partner. Assessing whether an entity is a VRE or VIE involves judgment. Upon the occurrence of certain events, management reviews and reconsiders its previous conclusion regarding the status of an entity as a VRE or a VIE. The Company consolidates VREs when it has control over significant operating, financial and investment decisions of the entity. When the Company lacks such control, but is deemed to have significant influence, the Company accounts for the entity under the equity method. Other investments in which the Company does not have rights to exercise significant influence are recorded at fair value, with changes in fair value reflected within Investment and other income. The Company consolidates VIEs when it is the primary beneficiary of the entity, which is defined as having the power to direct the activities that most significantly impact the VIE’s economic performance and the obligation to absorb losses of or the right to receive benefits from the entity that could potentially be significant to the VIE. The Company applies the equity method of accounting to VIEs where the Company is not the primary beneficiary, but has the ability to exercise significant influence over operating and financial matters of the VIE. Investments in Affiliates Substantially all of the Company’s Affiliates are considered VIEs and are either consolidated or accounted for under the equity method. A limited number of the Company’s Affiliates are considered VREs and most of these are accounted for under the equity method. When an Affiliate is consolidated, the portion of the Affiliate’s management equity owners’ earnings attributable to Owners’ Allocation is included in Net income (non-controlling interests) in the Consolidated Statements of Income. Undistributed Operating and Owners’ Allocation attributable to Affiliate management equity owners, along with their share of any tangible or intangible net assets, are presented within Non-controlling interests on the Consolidated Condensed Balance Sheets. Affiliate equity interests where the holder has certain rights to demand settlement are presented, at their current redemption values, as Redeemable non-controlling interests on the Consolidated Condensed Balance Sheets. The Company periodically issues, sells and repurchases the equity of its consolidated Affiliates. Because these transactions take place between entities that are under common control, any gains or losses attributable to these transactions are required to be included within Additional paid-in capital in the Consolidated Condensed Balance Sheets, net of any related income tax effects, in the period the transactions occur. When an Affiliate is accounted for under the equity method, the Company’s share of an Affiliate’s earnings or losses, net of amortization and impairments, is included in Equity method income (net) in the Consolidated Statements of Income and the Company’s interest in the Affiliate is reported in Equity method investments in Affiliates (net) in the Consolidated Condensed Balance Sheets. The Company’s share of income taxes incurred directly by Affiliates accounted for under the equity method is recorded within Income tax expense in the Consolidated Statements of Income. The Company periodically evaluates its equity method Affiliates for impairment. In such impairment evaluations, the Company assesses whether or not the fair value of the investment has declined below its carrying value for a period considered to be other-than-temporary. If the Company determines that a decline in fair value below the carrying value of the investment is other-than-temporary, then the carrying value of the investment is reduced to its fair value and the reduction is recorded in Equity method income (net). Affiliate Sponsored Investment Products The Company’s Affiliates sponsor various investment products where they also act as the investment advisor. These investment products are typically owned primarily by third-party investors; however, certain products are funded with general partner and seed capital investments from the Company and its Affiliates. Third-party investors in Affiliate sponsored investment products are generally entitled to substantially all of the economics of these products, except for the management and performance fees earned by the Company’s consolidated Affiliates or any gains or losses attributable to the Company’s or its consolidated Affiliates’ investments in these products. As a result, the Company does not generally consolidate these products unless the Company’s or its Affiliate’s interest in the product is considered substantial. When the Company’s or its Affiliate’s interest is considered substantial and the products are consolidated, the Company retains the specialized investment company accounting principles of the underlying products, and all of the underlying investments are carried at fair value in Investments in marketable securities, with corresponding changes in the investments’ fair values reflected in Investment and other income. Purchases and sales of securities are presented within purchases and sales by Affiliate sponsored consolidated products in the Consolidated Statements of Cash Flows. When the Company or its Affiliates no longer control these products, due to a reduction in ownership or other reasons, the products are deconsolidated with only the Company’s or its consolidated Affiliate’s investment in the product reported from the date of deconsolidation.

Investments in Marketable Sec_2

Investments in Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Marketable Securities [Abstract]
Schedule of Investments in Marketable Securities	The following is a summary of the cost, gross unrealized gains and losses and fair value of Investments in marketable securities: December 31, September 30, Cost $ 67.1 $ 128.3 Unrealized gains 13.0 15.8 Unrealized losses (2.3 ) (0.0 ) Fair value $ 77.8 $ 144.1

Investments in Affiliates and_2

Investments in Affiliates and Affiliate Sponsored Investment Products (Tables)	9 Months Ended
	Sep. 30, 2018
Variable Interest Entities
Schedule of Unconsolidated Assets and Liabilities of Equity Method Investments and Company's Risk of Loss	The net assets of unconsolidated VIEs attributable to Affiliate sponsored investment products, and the Company’s carrying value and maximum risk of loss, were as follows: December 31, 2017 September 30, 2018 Unconsolidated VIE Net Assets Carrying Value and Maximum Exposure to Loss Unconsolidated VIE Net Assets Carrying Value and Maximum Exposure to Loss Affiliate sponsored investment products $ 2,154.6 $ 10.2 $ 2,227.3 $ 1.0 The unconsolidated assets, net of liabilities and non-controlling interests of equity method Affiliates considered VIEs, and the Company’s maximum risk of loss, were as follows: December 31, 2017 September 30, 2018 Unconsolidated Carrying Value and Unconsolidated Carrying Value and Affiliates accounted for under the equity method $ 1,594.4 $ 2,765.7 $ 1,169.8 $ 2,530.8

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Company's Derivative Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s and its Affiliates’ derivative financial instruments measured at fair value on a recurring basis. As of December 31, 2017, the Company and its Affiliates did not have any significant derivative financial instruments. September 30, 2018 Assets (1) Liabilities (2) Forward contracts $ 1.0 $ 6.4 Put option — 21.6 Call option — (23.5 ) Total $ 1.0 $ 4.5 (1) Amounts are presented in Other investments and assets in the Consolidated Condensed Balance Sheets. (2) Amounts are presented in Other liabilities in the Consolidated Condensed Balance Sheets.
Schedule of Effect of Derivative Financial Instruments on the Consolidated Statements of Comprehensive Income and Statements of Income	The following table summarizes the effect of the derivative financial instruments on the Consolidated Statements of Comprehensive Income and the Consolidated Statements of Income. In the three and nine months ended September 30, 2017, the Company and its Affiliates did not have any significant derivative financial instruments. For the Three Months Ended September 30, 2018 For the Nine Months Ended September 30, 2018 Gain (Loss) Recognized in Other Comprehensive Income Gain (Loss) Recognized in Earnings from Excluded Components (1) Gain (Loss) Recognized in Other Comprehensive Income Gain (Loss) Recognized in Earnings from Excluded Components (1) Forward contracts $ (5.9 ) $ 0.5 $ (5.6 ) $ 0.5 Put option 1.6 — 1.6 — Call option 0.3 — 0.3 — Total $ (4.0 ) $ 0.5 $ (3.7 ) $ 0.5 (1) The excluded components are recorded as a reduction in Interest expense.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis	The following tables summarize the Company’s financial assets and liabilities that are measured at fair value on a recurring basis: Fair Value Measurements December 31, Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets Cash equivalents $ 40.4 $ 40.4 $ — $ — Investments in marketable securities 77.8 77.8 — — Derivative financial instruments (1) 0.2 — 0.2 — Financial Liabilities (2) Contingent payment arrangements $ 9.4 $ — $ — $ 9.4 Affiliate equity repurchase obligations 49.2 — — 49.2 Derivative financial instruments 0.6 — 0.6 — Fair Value Measurements September 30, Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets Cash equivalents $ 48.1 $ 48.1 $ — $ — Investments in marketable securities 144.1 144.1 — — Derivative financial instruments (1) 1.0 — 1.0 — Financial Liabilities (2) Contingent payment arrangements $ 4.3 $ — $ — $ 4.3 Affiliate equity repurchase obligations 28.7 — — 28.7 Derivative financial instruments 4.5 — 4.5 — __________________________ (1) Amounts are presented within Other investments and assets. (2) Amounts are presented within Other liabilities.
Schedule of Changes in Level 3 Assets and Liabilities	The following tables present the changes in level 3 liabilities: For the Three Months Ended September 30, 2017 2018 Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Balance, beginning of period $ 7.8 $ 70.7 $ 4.2 $ 36.9 Net realized and unrealized (gains) losses (1) 0.3 (0.2 ) 0.1 — Purchases and issuances (2) — 11.1 — 40.1 Settlements and reductions — (35.9 ) — (48.3 ) Balance, end of period $ 8.1 $ 45.7 $ 4.3 $ 28.7 Net change in unrealized (gains) losses relating to instruments still held at the reporting date (1) $ 0.3 $ — $ 0.1 $ — For the Nine Months Ended September 30, 2017 2018 Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Balance, beginning of period $ 8.6 $ 12.1 $ 9.4 $ 49.2 Net realized and unrealized (gains) losses (1) 2.3 (0.2 ) (0.3 ) — Purchases and issuances (2) — 161.5 — 86.0 Settlements and reductions (2.8 ) (127.7 ) (4.8 ) (106.5 ) Balance, end of period $ 8.1 $ 45.7 $ 4.3 $ 28.7 Net change in unrealized (gains) losses relating to instruments still held at the reporting date (1) $ 2.3 $ — $ 0.4 $ — ___________________________ (1) Accretion and changes in the expected value of the Company’s contingent payment arrangements and Affiliate equity repurchase obligations are recorded in Other expenses (net) in the Consolidated Statements of Income. (2) Includes transfers from Redeemable non-controlling interests.
Schedule of Quantitative Information used in Valuing Level 3 Liabilities	The following table presents certain quantitative information about the significant unobservable inputs used in valuing the Company’s level 3 fair value measurements: Quantitative Information About Level 3 Fair Value Measurements Valuation Techniques Unobservable Input Fair Value at Range at Fair Value at September 30, 2018 Range at September 30, 2018 Contingent payment arrangements Discounted cash flow Growth rates $ 9.4 7% - 8% $ 4.3 7% Discount rates 15% - 16% 15% Affiliate equity repurchase obligations Discounted cash flow Growth rates 49.2 0% - 11% 28.7 4% - 9% Discount rates 12% - 16% 14% - 16%
Schedule of Investments in Certain Entities that Calculate Net Asset Value	The following table summarizes the nature of the Company’s investments, unfunded commitments and any related liquidity restrictions or other factors that may impact the ultimate value realized: December 31, 2017 September 30, 2018 Category of Investment Fair Value Unfunded Commitments Fair Value Unfunded Commitments Private equity funds (1) $ 156.1 $ 98.8 $ 185.4 $ 130.4 Other funds (2) 8.9 — 7.4 — Other investments (3) $ 165.0 $ 98.8 $ 192.8 $ 130.4 ___________________________ (1) The Company uses NAV as a practical expedient one quarter in arrears (adjusted for current period calls and distributions) to determine the fair value. These funds primarily invest in a broad range of private equity funds, as well as making direct investments. Distributions will be received as the underlying assets are liquidated over the life of the funds, which is generally up to 15 years . (2) These are multi-disciplinary funds that invest across various asset classes and strategies, including long/short equity, credit and real estate. Investments are generally redeemable on a daily, monthly or quarterly basis. (3) Fair value attributable to the controlling interest was $80.1 million and $115.0 million as of December 31, 2017 and September 30, 2018 , respectively.
Schedule of Financial Assets and Liabilities Not Carried at Fair Value	The following table summarizes the Company’s other financial liabilities not carried at fair value: December 31, 2017 September 30, 2018 Carrying Value Fair Value Carrying Value Fair Value Fair Value Hierarchy Senior notes (1) $ 745.7 $ 765.2 $ 746.1 $ 743.8 Level 2 Convertible securities 309.9 549.8 311.8 498.7 Level 2 ___________________________ (1) The carrying value of the senior notes is reported in Senior debt.

Goodwill and Acquired Client _2

Goodwill and Acquired Client Relationships (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Goodwill	The following tables present the changes in the Company’s consolidated Affiliates’ Goodwill and components of Acquired client relationships (net) in the Consolidated Condensed Balance Sheets: Goodwill Balance, as of December 31, 2017 $ 2,662.5 Foreign currency translation (14.1 ) Balance, as of September 30, 2018 $ 2,648.4
Schedule of Changes in the Components of Acquired Client Relationships	Acquired Client Relationships (Net) Definite-lived Indefinite-lived Total Gross Book Value Accumulated Amortization Net Book Value Net Book Value Net Book Value Balance, as of December 31, 2017 $ 1,295.5 $ (874.5 ) $ 421.0 $ 1,028.7 $ 1,449.7 Intangible amortization and impairments — (76.5 ) (76.5 ) — (76.5 ) Foreign currency translation (1.9 ) — (1.9 ) (13.9 ) (15.8 ) Balance, as of September 30, 2018 $ 1,293.6 $ (951.0 ) $ 342.6 $ 1,014.8 $ 1,357.4

Equity Method Investments in _2

Equity Method Investments in Affiliates (Tables)	9 Months Ended
	Sep. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Changes in Equity Method Investments in Affiliates	The following table presents the change in Equity method investments in Affiliates (net): Equity Method Investments in Affiliates (Net) Balance, as of December 31, 2017 $ 3,304.7 Equity method earnings 300.3 Equity method intangible amortization and impairments (109.0 ) Distributions of earnings from equity method investments (410.3 ) Foreign currency translation (21.3 ) Other (9.1 ) Balance, as of September 30, 2018 $ 3,055.3

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-Based Compensation	The following table presents share-based compensation expense: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Share-based compensation $ 10.3 $ 11.7 $ 30.0 $ 33.5 Tax benefit 4.0 2.9 11.5 8.4
Schedule of Company Stock Option Transactions	The following table summarizes transactions in the Company’s stock options: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (Years) Unexercised options outstanding - December 31, 2017 0.6 $ 122.04 Options granted 0.0 179.54 Options exercised (0.1 ) 100.00 Options forfeited (0.0) 122.40 Unexercised options outstanding - September 30, 2018 0.5 130.30 4.0 Exercisable at September 30, 2018 0.1 136.33 2.7
Schedule of Fair Value of Options Granted and Assumptions	The weighted average grant date assumptions used to estimate the fair value of options granted were as follows: For the Nine Months Ended September 30, 2017 2018 Dividend yield 0.5 % 0.8 % Expected volatility 28.0 % 25.5 % Risk-free interest rate 2.1 % 2.8 % Expected life of options (in years) 5.7 5.7 Forfeiture rate — % — %
Schedule of Company Restricted Stock Units Transactions	The following table summarizes transactions in the Company’s restricted stock units: Restricted Stock Units Weighted Average Grant Date Value Unvested units - December 31, 2017 0.4 $ 162.32 Units granted 0.2 201.76 Units vested (0.0) 198.24 Units forfeited (0.0) 152.09 Unvested units - September 30, 2018 0.6 172.58

Redeemable Non-Controlling In_2

Redeemable Non-Controlling Interests (Tables)	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
Schedule of Changes in Redeemable Non-Controlling Interests	The following table presents the changes in Redeemable non-controlling interests: Redeemable Non-controlling interests Balance, as of December 31, 2017 $ 811.9 Changes attributable to consolidated products 64.9 Transfers to Other liabilities (86.0 ) Transfers from Non-controlling interests 30.0 Changes in redemption value 148.1 Balance, as of September 30, 2018 $ 968.9

Affiliate Equity (Tables)

Affiliate Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Affiliate Equity [Abstract]
Schedule of Affiliate Equity Compensation	The following table presents Affiliate equity expense: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Controlling interest $ 2.3 $ 6.1 $ 9.4 $ 10.9 Non-controlling interests 7.7 9.9 29.2 32.8 Total $ 10.0 $ 16.0 $ 38.6 $ 43.7
Schedule of Affiliate Equity Unrecognized Compensation Expense	The following table presents unrecognized Affiliate equity expense: Controlling Interest Remaining Life Non-controlling Interests Remaining Life December 31, 2017 $ 33.3 5 years $ 95.9 6 years September 30, 2018 36.8 5 years 120.0 6 years
Schedule of Changes in the Company's Interest in its Affiliates on the Controlling Interest's Equity	While the Company presents the current redemption value of Affiliate equity within Redeemable non-controlling interests, with changes in the current redemption value increasing or decreasing the controlling interest’s equity over time, the following table presents the cumulative effect that ownership changes had on the controlling interest’s equity related only to Affiliate equity transactions that settled during the applicable periods: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Net income (controlling interest) $ 125.4 $ 124.9 $ 374.2 $ 394.9 Decrease in controlling interest paid-in capital from Affiliate equity issuances (0.3 ) (0.5 ) (0.6 ) (3.8 ) Decrease in controlling interest paid-in capital from Affiliate equity repurchases (12.7 ) (31.7 ) (81.8 ) (63.8 ) Net income (controlling interest) including the net impact of Affiliate equity transactions $ 112.4 $ 92.7 $ 291.8 $ 327.3

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Schedule of Income Tax Provisions by Controlling and Noncontrolling Interests	The following table presents the consolidated provision for income taxes: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Controlling interest: Current tax $ 39.6 $ 33.8 $ 102.0 $ 107.4 Intangible-related deferred taxes 22.9 12.2 61.8 30.1 Other deferred taxes 1.6 0.2 18.7 1.2 Total controlling interest 64.1 46.2 182.5 138.7 Non-controlling interests: Current tax $ 2.1 $ 2.4 $ 5.9 $ 7.6 Deferred taxes (0.1 ) (0.1 ) (0.2 ) (0.2 ) Total non-controlling interests 2.0 2.3 5.7 7.4 Provision for income taxes $ 66.1 $ 48.5 $ 188.2 $ 146.1 Income before income taxes (controlling interest) $ 189.5 $ 171.1 $ 556.7 $ 533.6 Effective tax rate (controlling interest) (1) 33.8 % 27.0 % 32.8 % 26.0 % __________________________ (1) Taxes attributable to the controlling interest divided by Income before income taxes (controlling interest)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	The following is a reconciliation of the numerator and denominator used in the calculation of basic and diluted earnings per share available to common stockholders: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Numerator Net income (controlling interest) $ 125.4 $ 124.9 $ 374.2 $ 394.9 Interest expense on convertible securities, net of taxes 3.9 4.7 11.6 14.2 Net income (controlling interest), as adjusted $ 129.3 $ 129.6 $ 385.8 $ 409.1 Denominator Average shares outstanding (basic) 55.8 53.1 56.3 53.9 Effect of dilutive instruments: Stock options and restricted stock units 0.3 0.1 0.3 0.2 Convertible securities 2.2 2.2 2.2 2.2 Average shares outstanding (diluted) 58.3 55.4 58.8 56.3
Schedule of Shares Excluded from Calculation of Basic and Diluted Earnings Per Share	Average shares outstanding (diluted) in the table above excludes share-based awards that have not satisfied performance conditions and the anti-dilutive effect of the following: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2018 2017 2018 Stock options and restricted stock units 0.0 0.2 0.1 0.2

Comprehensive Income (Tables)

Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2018
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Tax Effects Allocated to Each Component of Other Comprehensive Income	The following tables present the tax effects allocated to each component of Other comprehensive income (loss): For the Three Months Ended September 30, 2017 2018 Pre-Tax Tax Benefit Net of Tax Pre-Tax Tax Benefit Net of Tax Foreign currency translation adjustment $ 53.0 $ — $ 53.0 $ (56.0 ) $ (0.4 ) $ (56.4 ) Change in net realized and unrealized gain (loss) on derivative securities 0.2 (0.1 ) 0.1 (0.0 ) — (0.0 ) Change in net unrealized gain (loss) on investment securities (6.8 ) 2.5 (4.3 ) — — — Other comprehensive income (loss) $ 46.4 $ 2.4 $ 48.8 $ (56.0 ) $ (0.4 ) $ (56.4 ) For the Nine Months Ended September 30, 2017 2018 Pre-Tax Tax Benefit Net of Tax Pre-Tax Tax Benefit Net of Tax Foreign currency translation adjustment $ 92.1 $ — $ 92.1 $ (47.1 ) $ (0.4 ) $ (47.5 ) Change in net realized and unrealized gain (loss) on derivative securities (0.7 ) (0.1 ) (0.8 ) 0.3 — 0.3 Change in net unrealized gain on investment securities (6.6 ) 3.2 (3.4 ) — — — Other comprehensive income (loss) $ 84.8 $ 3.1 $ 87.9 $ (46.8 ) $ (0.4 ) $ (47.2 )
Schedule of Components of Accumulated Other Comprehensive Income	The components of accumulated other comprehensive income (loss), net of taxes, were as follows: Foreign Currency Translation Adjustment Realized and Unrealized Gains (Losses) on Derivative Securities Unrealized Gains (Losses) on Investment Securities (1) Total Balance, as of December 31, 2017 $ (85.9 ) $ (0.4 ) $ 2.1 $ (84.2 ) Other comprehensive income before reclassifications (47.5 ) (0.0) — (47.5 ) Amounts reclassified — 0.3 (2.1 ) (1.8 ) Net other comprehensive income (loss) (47.5 ) 0.3 (2.1 ) (49.3 ) Balance, as of September 30, 2018 $ (133.4 ) $ (0.1 ) $ — $ (133.5 ) __________________________ (1) In connection with the Company’s adoption of ASU 2016-01, the unrealized losses on investment securities, which related to the non-controlling interests, were reclassified to Non-controlling interests.

Investments in Marketable Sec_3

Investments in Marketable Securities - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investments in marketable securities	$ 144,100,000		$ 144,100,000		$ 77,800,000
Proceeds received from sales of marketable securities	16,600,000	$ 23,600,000	42,600,000	$ 81,900,000
Net realized gains (losses) on sale of marketable securities	$ 0	$ 9,100,000	$ (4,000,000)	$ 24,200,000

Investments in Marketable Sec_4

Investments in Marketable Securities - Cost, Gross Unrealized Gains and Losses and Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Marketable Securities [Abstract]
Cost	$ 128.3	$ 67.1
Unrealized gains	15.8	13
Unrealized losses	0	(2.3)
Fair value	$ 144.1	$ 77.8

Investments in Affiliates and_3

Investments in Affiliates and Affiliate Sponsored Investment Products - Affiliated Accounted For Under Equity Method (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Variable Interest Entities
Carrying amount and maximum exposure to loss equity method investmetns considered VREs	$ 524.5	$ 539
Affiliates accounted for under the equity method
Variable Interest Entities
Unconsolidated VIE Net Assets	1,169.8	1,594.4
Carrying Value and Maximum Exposure to Loss	$ 2,530.8	$ 2,765.7

Investments in Affiliates and_4

Investments in Affiliates and Affiliate Sponsored Investment Products - Affiliated Sponsored Investment Products (Details) - Affiliate sponsored investment products - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Variable Interest Entities
Unconsolidated VIE Net Assets	$ 2,227.3	$ 2,154.6
Carrying Value and Maximum Exposure to Loss	$ 1	$ 10.2

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	Dec. 31, 2018	Sep. 30, 2018
Commitments and Contingencies
Co-investment commitments in partnership		$ 130,400,000
Consolidated Affiliates
Commitments and Contingencies
Contingent liability		12,700,000
Expected payments of contingent liability		4,500,000
Present value of expected payments of contingent liabilities		4,300,000
Consolidated Affiliates | Scenario, Forecast
Commitments and Contingencies
Expected payments of contingent liability	$ 2,500,000
Equity Method Investee
Commitments and Contingencies
Contingent liability		$ 150,000,000
Equity Method Investee | Scenario, Forecast
Commitments and Contingencies
Expected payments of contingent liability	$ 0

Senior Debt (Details)

Senior Debt (Details) - Sep. 30, 2018 - Unsecured Debt	USD ($)	GBP (£)
Revolver
Long-term debt
Total available borrowing	$ 1,450,000,000
Additional borrowing amount	350,000,000
Borrowings outstanding	$ 415,000,000
Term Loan
Long-term debt
Additional borrowing amount | £		£ 50,000,000
Principal amount at maturity | £		£ 290,000,000

Convertible Securities (Details

Convertible Securities (Details) - Junior Convertible Trust Preferred Securities	Aug. 10, 2018USD ($)$ / shares	Aug. 09, 2018	Sep. 30, 2018
Debt Instrument, Redemption [Line Items]
Stated interest rate			5.15%
Conversion ratio per share of common stock	0.2525	0.2500
Face amount of convertible security | $	$ 50
Adjusted conversion price (in dollars per share) | $ / shares	$ 198.02

Derivative Financial Instrume_3

Derivative Financial Instruments - Additional Information (Details) - Forward contracts £ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2018GBP (£)	Aug. 28, 2018$ / unit
Derivative [Line Items]
Cash collateral held from counterparty | $	$ 3,100,000	$ 3,100,000
Designated as Hedging Instrument | Net Investment Hedging
Derivative [Line Items]
Derivative notional amount	400,000,000	400,000,000	£ 285.8
Hedge ineffectiveness recorded in investment and other income | $	$ 0	$ 0
Designated as Hedging Instrument | Net Investment Hedging | Minimum
Derivative [Line Items]
Derivative, option strike price (in dollars per unit) | $ / unit				1.288
Designated as Hedging Instrument | Net Investment Hedging | Maximum
Derivative [Line Items]
Derivative, option strike price (in dollars per unit) | $ / unit				1.535

Derivative Financial Instrume_4

Derivative Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - Designated as Hedging Instrument - Derivatives in Net Investment Hedging Relationship $ in Millions	Sep. 30, 2018USD ($)
Other Investments
Derivative [Line Items]
Assets	$ 1	[1]
Other Liabilities
Derivative [Line Items]
Liabilities	4.5	[2]
Forward contracts | Other Investments
Derivative [Line Items]
Assets	1	[1]
Forward contracts | Other Liabilities
Derivative [Line Items]
Liabilities	6.4	[2]
Put option | Other Investments
Derivative [Line Items]
Assets	0	[1]
Put option | Other Liabilities
Derivative [Line Items]
Liabilities	21.6	[2]
Call option | Other Investments
Derivative [Line Items]
Assets	0	[1]
Call option | Other Liabilities
Derivative [Line Items]
Liabilities	$ (23.5)	[2]
[1]	Amounts are presented in Other investments and assets in the Consolidated Condensed Balance Sheets.
[2]	Amounts are presented in Other liabilities in the Consolidated Condensed Balance Sheets.

Derivative Financial Instrume_5

Derivative Financial Instruments - Effect on Statement of Comprehensive Income and Statement of Income (Details) - Designated as Hedging Instrument - Derivatives in Net Investment Hedging Relationship - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2018	Sep. 30, 2018
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		$ (4)	$ (3.7)
Interest Expense
Derivative [Line Items]
Gain (Loss) Recognized in Earnings from Excluded Components	[1]	0.5	0.5
Forward contracts
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		(5.9)	(5.6)
Forward contracts | Interest Expense
Derivative [Line Items]
Gain (Loss) Recognized in Earnings from Excluded Components	[1]	0.5	0.5
Put option
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		1.6	1.6
Put option | Interest Expense
Derivative [Line Items]
Gain (Loss) Recognized in Earnings from Excluded Components	[1]	0	0
Call option
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		0.3	0.3
Call option | Interest Expense
Derivative [Line Items]
Gain (Loss) Recognized in Earnings from Excluded Components	[1]	$ 0	$ 0
[1]	The excluded components are recorded as a reduction in Interest expense.

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured on a Recurring Basis (Details) - Fair Value Measured On A Recurring Basis - USD ($)		Sep. 30, 2018		Dec. 31, 2017
Financial Assets
Cash equivalents		$ 48,100,000		$ 40,400,000
Investments in marketable securities		144,100,000		77,800,000
Derivative financial instruments	[1]	1,000,000		200,000
Financial Liabilities
Contingent payment arrangements		4,300,000	[2]	9,400,000
Affiliate equity repurchase obligations		28,700,000	[2]	49,200,000
Derivative financial instruments	[2]	4,500,000		600,000
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets
Cash equivalents		48,100,000		40,400,000
Investments in marketable securities		144,100,000		77,800,000
Derivative financial instruments	[1]	0		0
Financial Liabilities
Contingent payment arrangements		0	[2]	0
Affiliate equity repurchase obligations		0	[2]	0
Derivative financial instruments	[2]	0		0
Significant Other Observable Inputs (Level 2)
Financial Assets
Cash equivalents		0		0
Investments in marketable securities		0		0
Derivative financial instruments	[1]	1,000,000		200,000
Financial Liabilities
Contingent payment arrangements		0	[2]	0
Affiliate equity repurchase obligations		0	[2]	0
Derivative financial instruments	[2]	4,500,000		600,000
Significant Unobservable Inputs (Level 3)
Financial Assets
Cash equivalents		0		0
Investments in marketable securities		0		0
Derivative financial instruments	[1]	0		0
Financial Liabilities
Contingent payment arrangements		4,300,000	[2]	9,400,000
Affiliate equity repurchase obligations		28,700,000	[2]	49,200,000
Derivative financial instruments	[2]	$ 0		$ 0
[1]	Amounts are presented within Other investments and assets.
[2]	Amounts are presented within Other liabilities.

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Contingent Payment Arrangements
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		$ 4.2	$ 7.8	$ 9.4	$ 8.6
Net realized and unrealized (gains) losses	[1]	0.1	0.3	(0.3)	2.3
Purchases and issuances	[2]	0	0	0	0
Settlements and reductions		0	0	(4.8)	(2.8)
Balance, end of period		4.3	8.1	4.3	8.1
Net change in unrealized (gains) losses relating to instruments still held at the reporting date	[1]	0.1	0.3	0.4	2.3
Affiliate Equity Repurchase Obligations
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		36.9	70.7	49.2	12.1
Net realized and unrealized (gains) losses	[1]	0	(0.2)	0	(0.2)
Purchases and issuances	[2]	40.1	11.1	86	161.5
Settlements and reductions		(48.3)	(35.9)	(106.5)	(127.7)
Balance, end of period		28.7	45.7	28.7	45.7
Net change in unrealized (gains) losses relating to instruments still held at the reporting date	[1]	$ 0	$ 0	$ 0	$ 0
[1]	Accretion and changes in the expected value of the Company’s contingent payment arrangements and Affiliate equity repurchase obligations are recorded in Other expenses (net) in the Consolidated Statements of Income.
[2]	Includes transfers from Redeemable non-controlling interests.

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information used in Valuing Level 3 Liabilities (Details) - Discounted Cash Flow $ in Millions	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Contingent Payment Arrangements | Growth rates
Quantitative information for Level 3 Fair Value Measurements Liabilities
Contingent payment arrangements, measurement input	0.07
Contingent Payment Arrangements | Growth rates | Minimum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Contingent payment arrangements, measurement input		0.07
Contingent Payment Arrangements | Growth rates | Maximum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Contingent payment arrangements, measurement input		0.08
Contingent Payment Arrangements | Discount rates
Quantitative information for Level 3 Fair Value Measurements Liabilities
Contingent payment arrangements, measurement input	0.15
Contingent Payment Arrangements | Discount rates | Minimum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Contingent payment arrangements, measurement input		0.15
Contingent Payment Arrangements | Discount rates | Maximum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Contingent payment arrangements, measurement input		0.16
Affiliate Equity Obligations | Growth rates | Minimum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Affiliate equity repurchase obligations, measurement input	0.04	0
Affiliate Equity Obligations | Growth rates | Maximum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Affiliate equity repurchase obligations, measurement input	0.09	0.11
Affiliate Equity Obligations | Discount rates | Minimum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Affiliate equity repurchase obligations, measurement input	0.14	0.12
Affiliate Equity Obligations | Discount rates | Maximum
Quantitative information for Level 3 Fair Value Measurements Liabilities
Affiliate equity repurchase obligations, measurement input	0.16	0.16
Significant Unobservable Inputs (Level 3) | Contingent Payment Arrangements
Quantitative information for Level 3 Fair Value Measurements Liabilities
Fair value liabilities	$ 4.3	$ 9.4
Significant Unobservable Inputs (Level 3) | Affiliate Equity Obligations
Quantitative information for Level 3 Fair Value Measurements Liabilities
Fair value liabilities	$ 28.7	$ 49.2

Fair Value Measurements - Inves

Fair Value Measurements - Investments Measured at Net Asset Value as Practical Expedient (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
NAV of investments at fair value
Life of funds (in years)		15 years
Other Investments
NAV of investments at fair value
Unfunded Commitments	[1]	$ 130.4	$ 98.8
Other Investments | Fair Value Measured at NAV
NAV of investments at fair value
Fair Value	[1]	192.8	165
Other Investments | Controlling Interest
NAV of investments at fair value
Fair Value		115	80.1
Private Equity Funds
NAV of investments at fair value
Unfunded Commitments	[2]	130.4	98.8
Private Equity Funds | Fair Value Measured at NAV
NAV of investments at fair value
Fair Value	[2]	185.4	156.1
Other Funds
NAV of investments at fair value
Unfunded Commitments	[3]	0	0
Other Funds | Fair Value Measured at NAV
NAV of investments at fair value
Fair Value	[3]	$ 7.4	$ 8.9
[1]	Fair value attributable to the controlling interest was $80.1 million and $115.0 million as of December 31, 2017 and September 30, 2018, respectively.
[2]	The Company uses NAV as a practical expedient one quarter in arrears (adjusted for current period calls and distributions) to determine the fair value. These funds primarily invest in a broad range of private equity funds, as well as making direct investments. Distributions will be received as the underlying assets are liquidated over the life of the funds, which is generally up to 15 years
[3]	These are multi-disciplinary funds that invest across various asset classes and strategies, including long/short equity, credit and real estate. Investments are generally redeemable on a daily, monthly or quarterly basis.

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Not Carried at Fair Value (Details) - Level 2 - USD ($) $ in Millions		Sep. 30, 2018	Dec. 31, 2017
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Senior notes	[1]	$ 746.1	$ 745.7
Convertible securities		311.8	309.9
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Senior notes		743.8	765.2
Convertible securities		$ 498.7	$ 549.8
[1]	The carrying value of the senior notes is reported in Senior debt.

Goodwill and Acquired Client _3

Goodwill and Acquired Client Relationships - Schedule of Changes in Goodwill (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill [Roll Forward]
Balance, as of December 31, 2017	$ 2,662.5
Foreign currency translation	(14.1)
Balance, as of September 30, 2018	$ 2,648.4

Goodwill and Acquired Client _4

Goodwill and Acquired Client Relationships - Schedule of Changes in the Components of Acquired Client Relationships (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Total
Beginning balance, net book value	$ 1,449.7
Ending balance, net book value	1,357.4
Acquired Client Relationships
Definite-lived
Beginning balance, gross book value	1,295.5
Beginning balance, accumulated amortization	(874.5)
Beginning balance, net book value	421
Amortization and impairments	(76.5)
Foreign currency translation	(1.9)
Ending balance, gross book value	1,293.6
Ending balance, accumulated amortization	(951)
Ending balance, net book value	342.6
Indefinite-lived
Beginning balance, net book value	1,028.7
Intangible amortization and impairments	0
Foreign currency translation	(13.9)
Ending balance, net book value	1,014.8
Total
Beginning balance, net book value	1,449.7
Amortization and impairments	(76.5)
Foreign currency translation	(15.8)
Ending balance, net book value	$ 1,357.4

Goodwill and Acquired Client _5

Goodwill and Acquired Client Relationships - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Intangible Assets
Goodwill impairment			$ 0
Amortization and impairment expenses of intangible assets	$ 30,100,000	$ 21,200,000	76,500,000	$ 65,100,000
Acquired Client Relationships
Estimated Future Amortization Expense of Finite-Lived Intangibles
Finite-lived intangible, future amortization expense in 2018	100,000,000		100,000,000
Finite-lived intangible, future amortization expense in 2019	90,000,000		90,000,000
Finite-lived intangible, future amortization expense in 2020	60,000,000		60,000,000
Finite-lived intangible, future amortization expense in 2021	35,000,000		35,000,000
Finite-lived intangible, future amortization expense in 2022	35,000,000		35,000,000
Acquired Client Relationships | Intangible amortization and impairments
Intangible Assets
Amortization and impairment expenses of intangible assets	$ 30,100,000	$ 21,200,000	$ 76,500,000	$ 65,100,000

Equity Method Investments in _3

Equity Method Investments in Affiliates - Change in Equity Method Investments (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Change in Equity Method Investments in Affiliates [Roll Forward]
Balance, as of December 31, 2017	$ 3,304.7
Distributions of earnings from equity method investments	(410.3)	$ (368)
Balance, as of September 30, 2018	3,055.3
Equity Method Investee
Change in Equity Method Investments in Affiliates [Roll Forward]
Balance, as of December 31, 2017	3,304.7
Equity method earnings	300.3
Equity method intangible amortization and impairments	(109)
Distributions of earnings from equity method investments	(410.3)
Foreign currency translation	(21.3)
Other	(9.1)
Balance, as of September 30, 2018	$ 3,055.3

Equity Method Investments in _4

Equity Method Investments in Affiliates - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Amortization expense during the period	$ 30.1		$ 21.2	$ 76.5	$ 65.1
Estimated Future Amortization Expense of Finite-Lived Intangibles
Carrying value of equity method investment in affiliate	3,055.3			3,055.3		$ 3,304.7
Acquired Client Relationships
Estimated Future Amortization Expense of Finite-Lived Intangibles
Finite-lived intangible, future amortization expense in 2018	100			100
Finite-lived intangible, future amortization expense in 2019	90			90
Finite-lived intangible, future amortization expense in 2020	60			60
Finite-lived intangible, future amortization expense in 2021	35			35
Finite-lived intangible, future amortization expense in 2022	35			35
Equity Method Investee
Estimated Future Amortization Expense of Finite-Lived Intangibles
Carrying value of equity method investment in affiliate	3,055.3			3,055.3		$ 3,304.7
Equity Method Investee | Investment One
Estimated Future Amortization Expense of Finite-Lived Intangibles
Impairment recognized on equity method investment in affiliate		$ 33.3
Impairment recognized on equity method investment in affiliate, net of tax		25
Carrying value of equity method investment in affiliate		$ 0
Revenue from equity method investment in affiliate	283.2		301.8	884.9	826.6
Net income from equity method investment in affiliate	135		178.3	443.3	471.3
Equity Method Investee | Acquired Client Relationships
Schedule of Equity Method Investments [Line Items]
Amortization expense during the period	22.2		$ 25.9	109	$ 71.7
Estimated Future Amortization Expense of Finite-Lived Intangibles
Finite-lived intangible, future amortization expense in 2018	100			100
Finite-lived intangible, future amortization expense in 2019	90			90
Finite-lived intangible, future amortization expense in 2020	90			90
Finite-lived intangible, future amortization expense in 2021	90			90
Finite-lived intangible, future amortization expense in 2022	$ 90			$ 90

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Related Party Transactions
Other liabilities	$ 166.5	$ 182.4
Prior Owner | Private Equity Investment Partnerships of Affiliate
Related Party Transactions
Other liabilities	51.7	61.2
Affiliated Entity | Other Liabilities
Related Party Transactions
Contingent payment arrangements liability	$ 4.3	$ 9.4

Share-Based Compensation - Shar

Share-Based Compensation - Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation	$ 11.7	$ 10.3	$ 33.5	$ 30
Tax benefit	2.9	$ 4	8.4	$ 11.5
Compensation expense related to share-based compensation	$ 67.1		$ 67.1		$ 63.5
Weighted average period over which compensation expense will be recognized			2 years

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of the Transactions of the Company's Stock Options (Details) shares in Millions	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Stock Options
Unexercised options outstanding at the beginning of the period (in shares) | shares	0.6
Options granted (in shares) | shares	0
Options exercised (in shares) | shares	(0.1)
Options forfeited (in shares) | shares	0
Unexercised options outstanding at the end of the period (in shares) | shares	0.5
Exercisable at the end of the period (in shares) | shares	0.1
Weighted Average Exercise Price
Unexercised options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 122.04
Options granted (in dollars per share) | $ / shares	179.54
Options exercised (in dollars per share) | $ / shares	100
Options forfeited (in dollars per share) | $ / shares	122.40
Unexercised options outstanding at the end of the period (in dollars per share) | $ / shares	130.30
Exercisable at the end of the period (in dollars per share) | $ / shares	$ 136.33
Weighted Average Remaining Contractual Life (Years)
Unexercised options outstanding at the end of the period (in years)	4 years
Exercisable at the end of the period (in years)	2 years 8 months 12 days

Share-Based Compensation - Sc_2

Share-Based Compensation - Schedule of Fair Value Options Granted and Assumptions (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation
Stock options granted, fair value		$ 0.8
Stock options granted, weighted average fair value (in dollars per share)	$ 48.64	$ 48.05
Stock Options
Share-based Compensation
Stock options granted, fair value	$ 1
Stock options, expiration period (in years)	7 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield	0.80%	0.50%
Expected volatility	25.50%	28.00%
Risk-fee interest rate	2.80%	2.10%
Expected life of options (in years)	5 years 8 months 12 days	5 years 8 months 12 days
Forfeiture rate	0.00%	0.00%
Stock Options | Minimum
Share-based Compensation
Stock options, vesting period (in years)	3 years
Stock Options | Maximum
Share-based Compensation
Stock options, vesting period (in years)	4 years

Share-Based Compensation - Sc_3

Share-Based Compensation - Schedule of Company Restricted Stock Units Transactions (Details) - Restricted Stock Units - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Restricted Stock Units
Unvested units at the beginning of the period (in shares)	0.4
Units granted (in shares)	0.2
Units vested (in shares)	0
Units forfeited (in shares)	0
Unvested units at the end of the period (in shares)	0.6
Weighted Average Grant Date Value
Unvested units at the beginning of the period (in dollars per share)	$ 162.32
Units granted (in dollars per share)	201.76
Units vested (in dollars per share)	198.24
Units forfeited (in dollars per share)	152.09
Unvested units at the end of the period (in dollars per share)	$ 172.58
Restricted stocks granted, fair value	$ 37.7	$ 36.7
Minimum
Weighted Average Grant Date Value
Restricted stock, vesting period (in years)	3 years
Maximum
Weighted Average Grant Date Value
Restricted stock, vesting period (in years)	4 years

Redeemable Non-Controlling In_3

Redeemable Non-Controlling Interests (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Redeemable Noncontrolling Interest [Roll Forward]
Balance, as of December 31, 2017	$ 811.9
Changes attributable to consolidated products	64.9
Transfers to Other liabilities	(86)
Transfers from Non-controlling interests	30	$ 56.8
Changes in redemption value	148.1
Balance, as of September 30, 2018	$ 968.9
Minimum
Noncontrolling Interest [Line Items]
Term of conditional right to put interest	5 years
Maximum
Noncontrolling Interest [Line Items]
Term of conditional right to put interest	15 years

Affiliated Equity - Additional

Affiliated Equity - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Affiliate Equity [Line Items]
Distributions paid to affiliate partners	$ 293.6	$ 266.8
Payments to acquire interest in affiliates	104.3	121.3
Issuance of interest in affiliates	6.3	$ 8.8
Other Assets
Affiliate Equity [Line Items]
Due from affiliates	17.8		$ 12.4
Other Liabilities
Affiliate Equity [Line Items]
Due to affiliates	$ 28.7		$ 49.2

Affiliate Equity - Summary of A

Affiliate Equity - Summary of Affiliate Recognized and Unrecognized Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Affiliate Equity [Line Items]
Affiliate equity expense	$ 16	$ 10	$ 43.7	$ 38.6
Non- controlling Interests
Affiliate Equity [Line Items]
Non-controlling interests	9.9	7.7	$ 32.8	29.2
Unrecognized Affiliate Equity Expense [Abstract]
Remaining Life (in years)			6 years		6 years
Non-Controlling Interest			$ 120		$ 95.9
Affiliated Entity
Affiliate Equity [Line Items]
Controlling interest	$ 6.1	$ 2.3	10.9	$ 9.4
Unrecognized Affiliate Equity Expense [Abstract]
Controlling Interest			$ 36.8		$ 33.3
Remaining Life (in years)			5 years		5 years

Affiliate Equity - Changes in t

Affiliate Equity - Changes in the Company's Interest in its Affiliates on the Controlling Interest's Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Affiliate Equity [Abstract]
Net income (controlling interest)	$ 124.9	$ 125.4	$ 394.9	$ 374.2
Decrease in controlling interest paid-in capital from Affiliate equity issuances	(0.5)	(0.3)	(3.8)	(0.6)
Decrease in controlling interest paid-in capital from Affiliate equity repurchases	(31.7)	(12.7)	(63.8)	(81.8)
Net income (controlling interest) including the net impact of Affiliate equity transactions	$ 92.7	$ 112.4	$ 327.3	$ 291.8

Income Taxes (Details)

Income Taxes (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provisional one-time net benefit from changes in U.S. tax laws		$ 194,100,000
Changes in provisional amount of initial one-time benefit recorded resulting from change in U.S. tax laws	$ 0

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Provisions by Controlling and Noncontrolling Interests (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Provision
Deferred taxes				$ 31.1	$ 80.3
Provision for income taxes		$ 48.5	$ 66.1	146.1	188.2
Non- controlling Interests
Income Tax Provision
Current tax		2.4	2.1	7.6	5.9
Deferred taxes		(0.1)	(0.1)	(0.2)	(0.2)
Provision for income taxes		2.3	2	7.4	5.7
Controlling Interest
Income Tax Provision
Current tax		33.8	39.6	107.4	102
Intangible-related deferred taxes		12.2	22.9	30.1	61.8
Other deferred taxes		0.2	1.6	1.2	18.7
Provision for income taxes		46.2	64.1	138.7	182.5
Income before income taxes (controlling interest)		$ 171.1	$ 189.5	$ 533.6	$ 556.7
Effective tax rate (controlling interest)	[1]	27.00%	33.80%	26.00%	32.80%
[1]	Taxes attributable to the controlling interest divided by Income before income taxes (controlling interest)

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator
Net income (controlling interest)	$ 124.9	$ 125.4	$ 394.9	$ 374.2
Interest expense on convertible securities, net of taxes	4.7	3.9	14.2	11.6
Net income (controlling interest), as adjusted	$ 129.6	$ 129.3	$ 409.1	$ 385.8
Denominator
Average shares outstanding (basic) (in shares)	53.1	55.8	53.9	56.3
Effect of dilutive instruments:
Stock options and restricted stock (in shares)	0.1	0.3	0.2	0.3
Convertible securities (in shares)	2.2	2.2	2.2	2.2
Average shares outstanding (diluted) (in shares)	55.4	58.3	56.3	58.8

Earnings Per Share - Schedule_2

Earnings Per Share - Schedule of Shares Excluded from Calculation of Basic and Diluted Earnings Per Share (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stock options and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0.2	0	0.2	0.1

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Details) - $ / shares shares in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Earnings Per Share [Abstract]
Number or shares repurchased during period (in shares)	0.8	2.5
Average price of shares repurchased during period (in dollars per share)	$ 146.85	$ 166.19

Comprehensive Income - Summary

Comprehensive Income - Summary of the Tax Effects Allocated to Each Component of Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss)
Pre-Tax	$ (56)	$ 46.4	$ (46.8)		$ 84.8
Tax Benefit (Expense)	(0.4)	2.4	(0.4)		3.1
Other comprehensive income (loss)	(56.4)	48.8	(47.2)		87.9
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss)
Pre-Tax	(56)	53	(47.1)		92.1
Tax Benefit (Expense)	(0.4)	0	(0.4)		0
Other comprehensive income (loss)	(56.4)	53	(47.5)		92.1
Change in net realized and unrealized gain (loss) on derivative securities
Accumulated Other Comprehensive Income (Loss)
Pre-Tax	0	0.2	0.3		(0.7)
Tax Benefit (Expense)	0	(0.1)	0		(0.1)
Other comprehensive income (loss)	0	0.1	0.3		(0.8)
Change in net unrealized gain (loss) on investment securities
Accumulated Other Comprehensive Income (Loss)
Pre-Tax		(6.8)			(6.6)
Tax Benefit (Expense)		2.5			3.2
Other comprehensive income (loss)		$ (4.3)	(2.1)	[1]	$ (3.4)
Change in net unrealized gain (loss) on investment securities attributable to noncontrolling interest
Accumulated Other Comprehensive Income (Loss)
Pre-Tax	0		0
Tax Benefit (Expense)	0		0
Other comprehensive income (loss)	$ 0		$ 0
[1]	In connection with the Company’s adoption of ASU 2016-01, the unrealized losses on investment securities, which related to the non-controlling interests, were reclassified to Non-controlling interests.

Comprehensive Income - Schedule

Comprehensive Income - Schedule of Components of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Components of Accumulated other comprehensive income, net of taxes
Beginning Balance				$ 4,578.5		$ 4,426.5
Other comprehensive income (loss)		$ (56.4)	$ 48.8	(47.2)		87.9
Ending Balance		4,321.2	4,404.3	4,321.2		4,404.3
Foreign Currency Translation Adjustment
Components of Accumulated other comprehensive income, net of taxes
Beginning Balance				(85.9)
Other comprehensive income before reclassifications				(47.5)
Amounts reclassified				0
Other comprehensive income (loss)		(56.4)	53	(47.5)		92.1
Ending Balance		(133.4)		(133.4)
Realized and Unrealized Gains (Losses) on Derivative Securities
Components of Accumulated other comprehensive income, net of taxes
Beginning Balance				(0.4)
Other comprehensive income before reclassifications				0
Amounts reclassified				0.3
Other comprehensive income (loss)		0	0.1	0.3		(0.8)
Ending Balance		(0.1)		(0.1)
Change in net unrealized gain (loss) on investment securities
Components of Accumulated other comprehensive income, net of taxes
Beginning Balance	[1]			2.1
Other comprehensive income before reclassifications	[1]			0
Amounts reclassified	[1]			(2.1)
Other comprehensive income (loss)			$ (4.3)	(2.1)	[1]	$ (3.4)
Ending Balance	[1]	0		0
Total
Components of Accumulated other comprehensive income, net of taxes
Beginning Balance				(84.2)
Other comprehensive income before reclassifications				(47.5)
Amounts reclassified				(1.8)
Other comprehensive income (loss)				(49.3)
Ending Balance		$ (133.5)		$ (133.5)
[1]	In connection with the Company’s adoption of ASU 2016-01, the unrealized losses on investment securities, which related to the non-controlling interests, were reclassified to Non-controlling interests.

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	Oct. 31, 2018USD ($)$ / unit	Oct. 31, 2018GBP (£)$ / unit	Sep. 30, 2018USD ($)	Sep. 30, 2018GBP (£)	Aug. 28, 2018$ / unit
Designated as Hedging Instrument | Forward contracts | Net Investment Hedging
Subsequent Event [Line Items]
Derivative notional amount			$ 400	£ 285,800,000
Designated as Hedging Instrument | Forward contracts | Net Investment Hedging | Minimum
Subsequent Event [Line Items]
Derivative, option strike price (in dollars per unit)					1.288
Designated as Hedging Instrument | Forward contracts | Net Investment Hedging | Maximum
Subsequent Event [Line Items]
Derivative, option strike price (in dollars per unit)					1.535
Unsecured Debt | Term Loan
Subsequent Event [Line Items]
Principal amount at maturity | £				290,000,000
Additional borrowing amount | £				£ 50,000,000
Subsequent Event | Designated as Hedging Instrument | Forward contracts | Net Investment Hedging
Subsequent Event [Line Items]
Derivative notional amount	$ 450	£ 325,300,000
Subsequent Event | Designated as Hedging Instrument | Forward contracts | Net Investment Hedging | Minimum
Subsequent Event [Line Items]
Derivative, option strike price (in dollars per unit)	1.318	1.318
Subsequent Event | Designated as Hedging Instrument | Forward contracts | Net Investment Hedging | Maximum
Subsequent Event [Line Items]
Derivative, option strike price (in dollars per unit)	1.448	1.448
Subsequent Event | Unsecured Debt | Term Loan
Subsequent Event [Line Items]
Principal amount at maturity | $	$ 450
Additional borrowing amount | $	$ 75