Invesco (IVZ) 10-K 23 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document Information [Line Items]
Entity Registrant Name	Invesco Ltd.
Entity Central Index Key	914,208
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		407,147,646
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 14.1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 2,006.4	$ 1,328
Unsettled fund receivables	793.8	672.9
Accounts receivable	622.5	544.2
Investments	674.6	795.3
Cash and cash equivalents of CIP	511.3	742.2
Accounts receivable and other assets of CIP	131.5	106.2
Investments of CIP	5,658	5,116.1
Assets held for policyholders	12,444.5	8,224.2
Prepaid assets	124.4	116.9
Other assets	61.7	95
Property, equipment and software, net	490.7	464.7
Intangible assets, net	1,558.7	1,399.4
Goodwill	6,590.7	6,129.2
Total assets	31,668.8	25,734.3
LIABILITIES
Accrued compensation and benefits	696.1	654.3
Accounts payable and accrued expenses	895.7	812.4
Debt of CIP	4,799.8	4,403.1
Other liabilities of CIP	498.8	673.4
Policyholder payables	12,444.5	8,224.2
Unsettled fund payables	783.8	659.3
Long-term debt	2,075.8	2,102.4
Deferred tax liabilities, net	275.5	309.7
Total liabilities	22,470	17,838.8
Commitments and contingencies (See Note 18)
TEMPORARY EQUITY
Redeemable noncontrolling interests in consolidated entities	243.2	283.7
Equity attributable to common shareholders:
Common shares ($0.20 par value; 1,050.0 million authorized; 490.4 million shares issued as of December 31, 2017 and 2016)	98.1	98.1
Additional paid-in-capital	6,282	6,227.4
Treasury shares	(2,781.9)	(2,845.8)
Retained earnings	5,489.1	4,833.4
Accumulated other comprehensive income/(loss), net of tax	(391.2)	(809.3)
Total equity attributable to Invesco Ltd.	8,696.1	7,503.8
Equity attributable to nonredeemable noncontrolling interests in consolidated entities	259.5	108
Total permanent equity	8,955.6	7,611.8
Total liabilities, temporary and permanent equity	$ 31,668.8	$ 25,734.3

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.2	$ 0.2
Common stock, shares authorized	1,050,000,000	1,050,000,000
Common stock, shares issued	490,400,000	490,400,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating revenues:
Investment management fees	$ 4,126.6	$ 3,773.1	$ 4,061.1
Service and distribution fees	852.8	823.6	855.4
Performance fees	113.3	44.3	85.9
Other	67.6	93.4	120.5
Total operating revenues	5,160.3	4,734.4	5,122.9
Operating expenses:
Third-party distribution, service and advisory	1,486.5	1,407.2	1,579.9
Employee compensation	1,537.4	1,378.8	1,395.5
Marketing	123.7	114.8	115.4
Property, office and technology	370.1	325.7	312
General and administrative	365.5	331.5	361.7
Total operating expenses	3,883.2	3,558	3,764.5
Operating income	1,277.1	1,176.4	1,358.4
Other income/(expense):
Equity in earnings of unconsolidated affiliates	44.7	9.3	35.1
Interest and dividend income	13.4	12.2	13
Interest expense	(94.8)	(93.4)	(81.7)
Other gains and losses, net	51.5	22.9	(1.5)
Other income/(expense) of CSIP, net	0	0	11.7
Other income/(expense) of CIP, net	137.3	79.2	27.1
Income before income taxes	1,429.2	1,206.6	1,362.1
Income tax provision	(268.2)	(338.3)	(398)
Net income	1,161	868.3	964.1
Net (income)/loss attributable to noncontrolling interests in consolidated entities	(33.7)	(14.1)	4
Net income attributable to Invesco Ltd.	$ 1,127.3	$ 854.2	$ 968.1
Basic:
Basic earnings per share (usd per share)	$ 2.75	$ 2.06	$ 2.26
Diluted:
Diluted earnings per share (usd per share)	2.75	2.06	2.26
Dividends declared per share	$ 1.15	$ 1.11	$ 1.06

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 1,161	$ 868.3	$ 964.1
Other comprehensive income/(loss), net of tax:
Currency translation differences on investments in foreign subsidiaries	389.4	(314.1)	(493.9)
Actuarial gain/(loss) related to employee benefit plans	21.1	(39.5)	11.1
Prior service credit related to employee benefit plans	0	(3.1)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	5.9	(5.5)	0
Reclassification of prior service (credit)/costs into employee compensation expense	0	(7)	(7.2)
Reclassification of actuarial (gains)/losses into employee compensation expense	2.5	1.5	2.2
Share of other comprehensive income/(loss) of equity method investments	(0.5)	(1.1)	(0.6)
Unrealized gains/(losses) on available-for-sale investments	5.1	5.2	(6)
Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses	(5.4)	0.3	(0.4)
Other comprehensive income/(loss)	418.1	(363.3)	(494.8)
Total comprehensive income/(loss)	1,579.1	505	469.3
Comprehensive (income)/loss attributable to noncontrolling interests in consolidated entities	(33.7)	(14.1)	4
Comprehensive income attributable to Invesco Ltd.	$ 1,545.4	$ 490.9	$ 473.3

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities:
Net income	$ 1,161	$ 868.3	$ 964.1
Adjustments to reconcile net income to net cash provided by/(used in) operating activities:
Amortization and depreciation	116.8	101.2	93.6
Share-based compensation expense	175.3	159.7	150.3
Other gains and losses, net	(39.4)	(22.9)	1.5
Other (gains)/losses of CSIP, net	0	0	0.8
Other (gains)/losses of CIP, net	(81)	(7.4)	37
Equity in earnings of unconsolidated affiliates	(44.7)	(9.3)	(35.1)
Dividends from unconsolidated affiliates	2.8	17.6	18.7
Changes in operating assets and liabilities:
(Increase)/decrease in cash held by CIP	226.2	(509.4)	39.9
(Increase)/decrease in cash held by CSIP	0	0	(10.5)
(Purchase)/sale of investments by CIP, net	(342.5)	(487.2)	0
(Purchase)/sale of trading investments	174.9	7	(159)
(Increase)/decrease in receivables	(3,419.4)	(3,392.2)	(4,489.9)
Increase/(decrease) in payables	3,440.7	3,445.9	4,517
Net cash provided by/(used in) operating activities	1,370.7	171.3	1,128.4
Investing activities:
Purchase of property, equipment and software	(111.7)	(147.7)	(124.5)
Purchase of available-for-sale investments	(7.9)	(25.9)	(44.9)
Sale of available-for-sale investments	79.5	59.3	51.1
Purchase of investments by CIP	(5,709.1)	(3,713.6)	(4,080.7)
Sale of investments by CIP	5,026.5	2,958.1	3,543.2
Purchase of investments by CSIP	0	0	(527.5)
Sale of investments by CSIP	0	0	524.2
Purchase of other investments	(169.8)	(125.4)	(167.8)
Sale of other investments	97.8	87.9	111.6
Returns of capital and distributions from unconsolidated partnership investments	132.8	38.6	50.5
Purchase of business	(299.2)	(121.9)	0
Net cash provided by/(used in) investing activities	(961.1)	(990.6)	(664.8)
Financing activities:
Proceeds from exercises of share options	0	0	3.7
Purchases of treasury shares	(63.8)	(577)	(623.7)
Dividends paid	(471.6)	(460.4)	(454.5)
Excess tax benefits from share-based compensation	0	(1.7)	21.2
Third-party capital invested into CIP	449.4	386.7	113.5
Third-party capital distributed by CIP	(105.4)	(91.5)	(120)
Third-party capital invested into CSIP	0	0	31.2
Third-party capital distributed by CSIP	0	0	(25.9)
Borrowings of debt of CIP	2,812.4	1,327.9	2,091.8
Repayments of debt of CIP	(2,410.1)	(171.5)	(1,573.1)
Net borrowings/(repayments) under credit facility	28.7	(28.7)	0
Proceeds from issuance of senior notes	0	0	495.5
Payment of contingent consideration	(13.2)	(13.1)	(11.3)
Net cash provided by/(used in) financing activities	169	428.1	(51.6)
Increase/(decrease) in cash and cash equivalents	578.6	(391.2)	412
Foreign exchange movement on cash and cash equivalents	99.8	(132.2)	(74.8)
Cash and cash equivalents, beginning of year	1,328	1,851.4	1,514.2
Cash and cash equivalents, end of year	2,006.4	1,328	1,851.4
Supplemental Cash Flow Information:
Interest paid	(85.4)	(81.2)	(67.5)
Interest received	3.1	5.8	8.8
Taxes paid	$ (256.5)	$ (299.1)	$ (388.7)

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Common Shares [Member]	Additional Paid-In-Capital [Member]	Treasury Shares [Member]	Retained Earnings [Member]	Retained Earnings Appropriated for Investors in CIP [Member]	Accumulated Other Comprehensive Income [Member]	Total Equity Attributable to Common Shareholders [Member]	Nonredeemable Noncontrolling Interests in Consolidated Entities [Member]	Redeemable noncontrolling interest [Member]	Redeemable Noncontrolling Interests [Domain]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment for adoption of ASUs | Accounting Standards Update 2014-13 [Member]	$ (17.6)	$ 0	$ 0	$ 0	$ 0	$ (17.6)	$ 0	$ (17.6)	$ 0
Beginning balance at Dec. 31, 2014	9,119.8	98.1	6,133.6	(1,898.1)	3,926	17.6	48.8	8,326	793.8
Beginning Balance, as adjusted at Dec. 31, 2014	9,102.2	98.1	6,133.6	(1,898.1)	3,926	0	48.8	8,308.4	793.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	965.2				968.1			968.1	(2.9)
Other comprehensive income (loss)	(494.8)						(494.8)	(494.8)
Change in noncontrolling interests in consolidated entities, net	19.5								19.5
Dividends	(454.5)				(454.5)			(454.5)
Employee share plans:
Share-based compensation	150.3		150.3					150.3
Vested shares	0		(109.2)	(109.2)
Stock Issued During Period, Value, Stock Options Exercised	(3.7)		(2.1)	(5.8)				(3.7)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	21.2		21.2					21.2
Other share awards	6.6	0	2.7	3.9	0	0	0	6.6	0
Treasury Stock, Value, Acquired, Cost Method	(623.7)		1.2	(624.9)				(623.7)
Ending balance at Dec. 31, 2015	8,695.7	98.1	6,197.7	(2,404.1)	4,439.6	$ 0	(446)	7,885.3	810.4
Beginning Balance at Dec. 31, 2014											$ 165.5
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income											(1.1)
Change in noncontrolling interests in consolidated entities, net											(2.9)
Ending Balance at Dec. 31, 2015											167.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment for adoption of ASUs | Accounting Standards Update 2015-02 [Member]	(733.5)							0	(733.5)		226.6
Beginning Balance, as adjusted at Dec. 31, 2015	7,962.2	98.1	6,197.7	(2,404.1)	4,439.6		(446)	7,885.3	76.9	$ 393.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	853.3				854.2			854.2	(0.9)
Other comprehensive income (loss)	(363.3)						(363.3)	(363.3)
Change in noncontrolling interests in consolidated entities, net	32								32
Dividends	(460.4)				(460.4)			(460.4)
Employee share plans:
Share-based compensation	159.7		159.7					159.7
Vested shares	0		(102.3)	(102.3)
Other share awards	7		0.8	6.2				7
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	1.7		1.7					1.7
Treasury Stock, Value, Acquired, Cost Method	(577)		(26.8)	(550.2)				(577)
Ending balance at Dec. 31, 2016	7,611.8	98.1	6,227.4	(2,845.8)	4,833.4		(809.3)	7,503.8	108
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income											15
Change in noncontrolling interests in consolidated entities, net											125.2
Ending Balance at Dec. 31, 2016											283.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,131.8				1,127.3			1,127.3	4.5
Other comprehensive income (loss)	418.1						418.1	418.1
Change in noncontrolling interests in consolidated entities, net	147								147
Dividends	(471.6)				(471.6)			(471.6)
Employee share plans:
Share-based compensation	175.3		175.3					175.3
Vested shares	0		(123)	(123)
Other share awards	7		2.3	4.7				7
Treasury Stock, Value, Acquired, Cost Method	(63.8)			(63.8)				(63.8)
Ending balance at Dec. 31, 2017	$ 8,955.6	$ 98.1	$ 6,282	$ (2,781.9)	$ 5,489.1		$ (391.2)	$ 8,696.1	$ 259.5
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income											29.2
Change in noncontrolling interests in consolidated entities, net											(69.7)
Ending Balance at Dec. 31, 2017											$ 243.2

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
ACCOUNTING POLICIES	ACCOUNTING POLICIES Corporate Information Invesco Ltd. (Parent) and all of its consolidated entities (collectively, the company or Invesco) provide retail and institutional clients with an array of global investment management capabilities. The company operates globally and its sole business is investment management. Basis of Accounting and Consolidation The Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States and with rules and regulations of the Securities and Exchange Commission and consolidate the financial statements of the Parent and all of its controlled subsidiaries. In the opinion of management, the Consolidated Financial Statements reflect all adjustments, consisting of normal recurring accruals, which are necessary for the fair presentation of the financial condition and results of operations for the periods presented. All significant intercompany transactions, balances, revenues and expenses are eliminated upon consolidation. The company provides investment management services to, and has transactions with, various retail mutual funds and similar entities, private equity funds, real estate funds, fund-of-funds, collateralized loan obligations (CLOs), and other investment products sponsored by the company in the normal course of business for the investment of client assets. The company serves as the investment manager, making day-to-day investment decisions concerning the assets of these products. In addition to consolidating the financial statements of the Parent and all of its controlled subsidiaries, the Consolidated Financial Statements include the consolidation of certain investment products (Consolidated Investment Products or CIP) that meet the definition of either a voting rights entity (VOE), if the company is deemed to have a controlling financial interest in the fund, or a variable interest entity (VIE), if the company has been deemed to be the primary beneficiary of the fund. Certain of these investment products, typically CLOs, funds that are structured as partnership entities (such as private equity funds, real estate funds, and fund-of-funds), and certain non-U.S. mutual funds, are considered, for accounting and consolidation analysis purposes, to be VIEs if the VIE criteria are met. A VIE, in the context of the company and its managed funds, is a fund that does not have sufficient equity to finance its operations without additional subordinated financial support, or a fund for which the risks and rewards of ownership are not directly linked to voting interests. If the company is deemed to have the power to direct the activities of the fund that most significantly impact the fund's economic performance, and the obligation to absorb losses/right to receive benefits from the fund that could potentially be significant to the fund, then the company is deemed to be the fund's primary beneficiary and is required to consolidate the fund. The company's economic risk with respect to each investment in a CIP is limited to its equity ownership and any uncollected management and performance fees. See Note 19 , "Consolidated Investment Products," for additional information regarding the impact of CIP. Consolidation Analysis The company inventories its funds by vehicle type on a quarterly basis. The company assesses modifications to existing funds on an ongoing basis to determine if a significant reconsideration event has occurred. The consolidation analysis includes a detailed review of the terms of the fund's governing documents and a comparison of the significant terms against the consolidation criteria in ASC Topic 810, including a determination of whether the fund is a VIE or a VOE. Seed money and co-investments in managed funds in which the company has determined that it is the primary beneficiary or in which the company has a controlling financial interest are consolidated if the impact of doing so is deemed material. Otherwise, these investments are accounted for as described in the “Investments” accounting policy below. Upon consolidation of an investment product, the company's gain or loss on its investment (before consolidation) eliminates with the company's share of the offsetting loss or gain in the fund. Upon consolidation of CLOs, the company's and the funds' accounting policies are effectively aligned, resulting in the reclassification of the company's gain or loss (representing the changes in the market value of the company's holding in the consolidated fund) from other comprehensive income into other gains/losses. The net impact from consolidation of funds previously carried as available-for-sale investments to net income attributable to Invesco Ltd. in each period primarily represents the changes in the value of the company's holdings in its consolidated CLOs. Consolidation of CLOs A significant portion of VIEs are CLOs. CLOs are investment vehicles created for the sole purpose of issuing collateralized loan instruments that offer investors the opportunity for returns that vary with the risk level of their investment. The notes issued by the CLOs are backed by diversified collateral asset portfolios consisting primarily of loans or structured debt. For managing the collateral of the CLO entities, the company earns investment management fees, including in some cases subordinated management fees, as well as contingent performance fees. The company has invested in certain of the entities, generally taking a portion of the unrated, junior subordinated position. The company's investments in CLOs are generally subordinated to other interests in the entities and entitle the company and other subordinated tranche investors to receive the residual cash flows, if any, from the entities. The company's subordinated interest can take the form of (1) subordinated notes, (2) income notes or (3) preference/preferred shares. The company has determined that, although the junior tranches have certain characteristics of equity, they should be accounted for and disclosed as debt on the company's Consolidated Balance Sheets, as the subordinated and income notes have a stated maturity indicating a date for which they are mandatorily redeemable. The preference shares are also classified as debt, as redemption is required only upon liquidation or termination of the CLO and not of the company. The company determined that it was the primary beneficiary of certain CLOs, as it has the power to direct the activities of the CLOs that most significantly impact the CLOs' economic performance, and the obligation to absorb losses/right to receive benefits from the CLOs that could potentially be significant to the CLOs. The primary beneficiary assessment includes an analysis of the rights of the company in its capacity as investment manager. In some CLOs, the company's role as investment manager provides that the company contractually has the power, as defined in ASC Topic 810, to direct the activities of the CLOs that most significantly impact the CLOs' economic performance, such as managing the collateral portfolio and the CLOs' credit risk. In other CLOs, the company determined that it does not have this power in its role as investment manager due to certain rights held by other investors in the products or restrictions that limit the company's ability to manage the collateral portfolio and its credit risk. Additionally, the primary beneficiary assessment includes an analysis of the company's rights to receive benefits and obligations to absorb losses associated with its first loss position and management/performance fees. The company has elected the fair value option under ASC Topic 825-10-25 to measure the assets of all consolidated CLOs at fair value. All of the investments held by VIEs are presented at fair value in the company's Consolidated Balance Sheets at December 31, 2017 and 2016 . The company adopted Accounting Standards Update 2014-13, "Measuring the Financial Assets and the Financial Liabilities of a Consolidated Collateralized Financing Entity" (ASU 2014-13) on January 1, 2015, and accordingly the notes issued by consolidated CLOs are no longer carried at fair value but are now measured under the measurement alternative discussed in ASU 2014-13. The measurement alternative requires that the reporting entity measure both the financial assets and the fair value of the financial liabilities of the CFE by using the more observable of the fair value of the financial assets and the fair value of the financial liabilities, removing any measurement difference previously recorded as net income (loss) attributable to noncontrolling interests in consolidated entities and as an adjustment to retained earnings appropriated for investors in CIP. The company’s subsequent earnings from consolidated CLOs reflect changes in fair value of its own economic interests in the CLOs. Gains or losses on assets and liabilities of the CLOs are not attributed to noncontrolling interests but are offset in other gains/(losses) of CIP. Consolidation of Private Equity, Real Estate, and Fund-of-Funds The company also consolidates certain private equity funds and from time to time real estate funds that are structured as partnerships in which the company is the general partner receiving a management and/or performance fee. Private equity investments made by the underlying funds consist of direct investments in, or fund investments in other private equity funds that hold direct investments in, equity or debt securities of operating companies that are generally not initially publicly traded. Private equity funds are considered investment companies and are therefore accounted for under ASC Topic 946, “Financial Services - Investment Companies.” The company has retained the specialized industry accounting principles of these investment products in its Consolidated Financial Statements. See Note 19 , “Consolidated Investment Products,” for additional details. Consolidation basis The Consolidated Financial Statements have been prepared primarily on the historical cost basis; however, certain items are presented using other bases such as fair value, where such treatment is required or voluntarily elected, as discussed above. The financial statements of subsidiaries, with the exception of certain CIP, are prepared for the same reporting period as the Parent and use consistent accounting policies, which, where applicable, have been adjusted to U.S. GAAP from local generally accepted accounting principles or reporting regulations. The financial information of certain CIP is included in the company's Consolidated Financial Statements on a one -month or a three -month lag based upon the availability of fund financial information. Noncontrolling interests in consolidated entities represents the interests in certain entities consolidated by the company either because the company has control over the entity or has determined that it is the primary beneficiary, but of which the company does not own all of the entity's equity. To the extent that noncontrolling interests represent equity which is redeemable or convertible for cash or other assets at the option of the equity holder, these are deemed to represent temporary equity, and are classified as equity attributable to redeemable noncontrolling interests in the Consolidated Balance Sheets. Nonredeemable noncontrolling interests are classified as a component of permanent equity. Use of Estimates In preparing the Consolidated Financial Statements, management is required to make estimates and assumptions that affect reported revenues, expenses, assets, liabilities, and disclosure of contingent liabilities. The primary estimates and assumptions made relate to goodwill and intangible impairment, certain investments which are carried at fair value, post-employment benefit plan obligations, and taxes. Additionally, estimation is involved when determining investment and debt valuation for certain CIP; however, changes in the fair values of these amounts are largely offset by noncontrolling interests. Use of available information and application of judgment are inherent in the formation of estimates. Actual results in the future could differ from such estimates and the differences may be material to the Consolidated Financial Statements. Reclassifications The presentation of certain prior period amounts has been reclassified to be consistent with the current period presentation. Such reclassifications had no impact on total operating revenues, operating expenses, net income, total assets, total liabilities, or equity attributable to Invesco Ltd. Acquisition Accounting In accordance with ASC Topic 805, “Business Combinations," any excess of the cost of the acquisition over the fair values of the identifiable net assets acquired attributable to the company is recognized as goodwill. With certain exceptions, 100% of the fair values of assets acquired, liabilities assumed, and noncontrolling interests is recognized in acquisitions of less than a 100% controlling interest when the acquisition constitutes a change in control of the acquired entity. Additionally, when partial ownership in an acquiree is obtained and it is determined that the company controls the acquiree, the assets acquired, liabilities assumed and any noncontrolling interests are recognized and consolidated at 100% of their fair values at that date, regardless of the percentage ownership in the acquiree. As goodwill is calculated as a residual, all goodwill of the acquired business, not just the company's share, is recognized under this “full-goodwill” approach. Noncontrolling interests are stated at the noncontrolling shareholder's proportion of the pre-acquisition carrying values of the acquired net assets. The results of entities acquired or sold during the year are included from or to the date control changes. Contingent consideration obligations that are elements of consideration transferred are recognized as of the acquisition date as part of the fair value transferred in exchange for the acquired business. Acquisition-related costs incurred in connection with a business combination are expensed. Cash and Cash Equivalents Cash and cash equivalents consist of cash held at banks and short-term investments with a maturity upon acquisition of three months or less. Cash and cash equivalents of CIP are not available for general use by the company. Cash balances may not be readily accessible to the Parent due to capital adequacy requirements of certain of our subsidiaries. These and other similar provisions of applicable laws and regulations may have the effect of limiting withdrawals of capital, repayment of intercompany loans and payment of dividends by such entities. All of our regulated EU subsidiaries are subject to consolidated capital requirements under EU Directives, including those arising from the EU's Capital Requirements Directive and the U.K.'s Internal Capital Adequacy Assessment Process (ICAAP), and capital is maintained within this sub-group to satisfy these regulations. We meet these requirements in part by holding cash and cash equivalents. This retained cash can be used for general business purposes in the European sub-group in the countries where it is located. Due to the capital restrictions, the ability to transfer cash between certain jurisdictions may be limited. In addition, transfers of cash between international jurisdictions may have adverse tax consequences. The company is in compliance with all regulatory minimum net capital requirements. In addition, the company is required to hold cash deposits with clearing organizations or to otherwise segregate cash to maintain compliance with federal and other regulations in connection with its UIT broker dealer entity. At December 31, 2017 these cash deposits totaled $11.4 million (year ended December 31, 2016 : $11.4 million ). Unsettled Fund Receivables and Payables The company records unsettled fund receivables from underlying fund investors in certain fund products outside the U.S. when these investors place unsettled investments into the funds. Additionally, the company records unsettled fund receivables from certain non-U.S. funds during the settlement period when underlying fund investors redeem their holdings. Settlement periods for both receivables from underlying investors and funds are generally less than four days. Additionally, in its capacity as sponsor of UITs, the company records receivables from brokers, dealers, and clearing organizations for unsettled sell trades of securities and UITs in addition to receivables from customers for unsettled sell trades of UITs. The company also records payables to brokers, dealers, and clearing organization for unsettled buy trades of securities and UITs in addition to payables to customers for unsettled buy trades of securities and UITs. The presentation of the unsettled fund receivables and substantially offsetting payables at trade date reflects the legal relationship between the underlying investor and the company. Accounts Receivable and Payable Accounts receivable and payable are recorded at their original invoice amounts. Accounts receivable are also recorded less any allowance for uncollectible amounts. Investments The majority of the company’s investment balances relate to balances held in affiliated funds. In the normal course of business, the company invests in various types of affiliated investment products, either as “seed money” or as longer-term investments alongside third-party investors, typically referred to as “co-investments.” Seed money investments are investments held in Invesco managed funds with the purpose of providing capital to the funds during their development periods to allow the funds to achieve critical mass, establish their track records, and obtain third-party investments. Seed money may also be held for regulatory purposes in certain jurisdictions. Co-investments are often required of the investment manager by third-party investors in closed-ended funds to demonstrate an aligning of the investment manager’s interests with those of the third-party investors. The company also invests in affiliated funds in connection with its deferred compensation plans, whereby certain employees defer portions of their annual bonus into funds. Investments are categorized in this Report as available-for-sale, trading, equity method, foreign time deposits, and other investments. See Note 3 “Investments” for additional details. Available-for-sale investments include seed money, co-investments in affiliated CLOs, and investments in other debt securities. Available-for-sale investments are measured at fair value. Gains or losses arising from changes in the fair value of available-for-sale investments are recognized in accumulated other comprehensive income, net of tax, until the investment is sold or otherwise disposed of, or if the investment is determined to be other-than-temporarily impaired, at which time the cumulative gain or loss previously reported in equity is included in income. The specific identification method is used to determine the realized gain or loss on securities sold or otherwise disposed. Trading investments include investments held to settle the company’s deferred compensation plan liabilities, seed money, as well as trading and investing activities in equity and debt securities entered into in its capacity as sponsor of UITs, and other equity securities. Trading securities are securities bought and held principally for the purpose of selling them in the near term. Trading investments are measured at fair value. Gains or losses arising from changes in the fair value of trading investments are included in income. Equity method investments include investments over which the company is deemed to have significant influence, including corporate joint ventures and non-controlled entities in which the company's ownership is between 20 and 50 percent, and co-investments in certain managed funds generally structured as partnerships or similar vehicles. Investments in joint ventures are investments jointly controlled by the company and external parties. Co-investments in managed funds structured as partnerships or similar vehicles include private equity, real estate, and fund-of-funds. The equity method of accounting requires that the investment is initially recorded at cost, including any excess value paid over the book value of the investment acquired. The carrying amount of the investment is increased or decreased to recognize the company's share of the after-tax profit or loss of the investee after the date of acquisition. The proportionate share of income or loss is included in equity in earnings of unconsolidated affiliates in the Consolidated Statements of Income, and the proportionate share of other comprehensive income or loss is included in accumulated other comprehensive income in the Consolidated Balance Sheets. Seed money and co-investments in managed funds are required to be consolidated by the company if certain criteria are met. Upon consolidation of material balances, the company’s seed money or co-investment balance is eliminated, and the underlying investments of the managed fund are reflected on the company’s Consolidated Balance Sheets at fair value. These underlying investments are presented in the company's Consolidated Financial Statements as CIP investments. See “Basis of Accounting and Consolidation” for additional information regarding the consolidation criteria. If the company subsequently determines that it no longer controls the managed funds in which it has invested, the company will deconsolidate the funds. Any remaining holding in the managed funds is then accounted for on the bases described above. Fair value is determined using a valuation hierarchy (discussed in Note 2 , “Fair Value of Assets and Liabilities”), generally by reference to an active trading market, using quoted closing or bid prices as of each reporting period end. When a readily ascertainable market value does not exist for an investment, the fair value is calculated based on the expected cash flows of its underlying net asset base, taking into account applicable discount rates and other factors. Judgment is used to ascertain if a formerly active market has become inactive and in determining fair values when markets have become inactive. The company evaluates the carrying value of investments for impairment on a quarterly basis. In its impairment analysis, the company takes into consideration numerous criteria, including the duration and extent of any decline in fair value, the intent and ability of the company to hold the security for a period of time sufficient for a recovery in value, recent events specific to the issuer or industry and external credit ratings and recent downgrades with respect to issuers of debt securities held. If the decline in value is determined to be other-than-temporary, the carrying value of the security is generally written down to fair value through the income statement. If the fair value of a debt security, however, is less than its amortized cost, the decline in value is determined to be other-than-temporary, and the company intends to sell the debt security or it is more likely than not that the company will be required to sell the debt security before the recovery of its amortized cost basis, the entire difference between the investment's amortized cost basis and its fair value is recognized as an other-than-temporary impairment through the income statement. If the company does not intend to sell the debt security, and it is not more likely than not that the company will be required to sell the debt security before recovery of its amortized cost basis, then the other-than-temporary impairment is separated into two components: a) the amount representing the credit loss, which is recorded as a charge in the Consolidated Statements of Income, and b) the amount related to all other factors, which is recognized in the Consolidated Statements of Comprehensive Income, net of tax. Assets Held for Policyholders and Policyholder Payables One of the company's subsidiaries, Invesco Perpetual Life Limited, is an insurance entity that was established to facilitate retirement savings plans in the U.K. The entity holds assets that are managed for its clients on its balance sheet with an equal and offsetting liability to the policyholders, which is linked to the value of the investments. The investments are legally segregated and are generally not subject to claims that arise from any of the company's other businesses. Investments and policyholder payables held by this business meet the definition of financial instruments and are carried in the Consolidated Balance Sheets as separate account assets and liabilities at fair value in accordance with ASC Topic 944, “Financial Services - Insurance.” Changes in fair value are recorded and offset to zero in the Consolidated Statements of Income in other operating revenues. Management fees earned from policyholder investments are accounted for as described in the company's revenue recognition accounting policy. Deferred Sales Commissions Mutual fund shares sold without a sales commission at the time of purchase typically have an asset-based fee (12b-1 fee) that is charged to the fund over a period of years and a contingent deferred sales charge (CDSC). The CDSC is an asset-based fee that is charged to investors that redeem during a stated period. Commissions paid at the date of sale to brokers and dealers for sales of mutual funds that have a CDSC are capitalized and amortized over a period not to exceed the redemption period of the related fund (generally up to six years ). The deferred sales commission asset, which is included in prepaid assets in our Consolidated Balance Sheets, is reviewed periodically for impairment by reviewing the recoverability of the asset based on estimated future fees to be collected. Property, Equipment, Software and Depreciation Property, equipment and software includes owned property, leasehold improvements, computer hardware/software and other equipment and is stated at cost less accumulated depreciation or amortization and any previously recorded impairment in value. Expenditures for major additions and improvements are capitalized; minor replacements, maintenance and repairs are charged to expense as incurred. Amounts incurred are presented as work-in-progress until the construction or purchase of the property and equipment is substantially complete and ready for its intended use, which, at that point, will begin to be depreciated or amortized. Depreciation is provided on property and equipment at rates calculated to write off the cost, less estimated residual value, of each asset on a straight-line basis over its expected useful life: owned buildings over 50 years , leasehold improvements over the shorter of the lease term or useful life of the improvement; and computers and other various equipment between three and seven years. Purchased and internally developed software is capitalized where the related costs can be measured reliably, and it is probable that the asset will generate future economic benefits, and amortized into operating expenses on a straight-line basis over its useful life, generally over five to seven years. The company capitalizes qualified internal and external costs incurred during the application development stage for internally developed software in accordance with ASC Topic 350-40, “Intangibles - Goodwill and Other - Internal-Use Software.” The company reevaluates the useful life determination for property and equipment each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life. On sale or retirement, the asset cost and related accumulated depreciation are removed from the Consolidated Financial Statements and any related gain or loss is reflected in income. The carrying amounts of property and equipment are reviewed for impairment when events or changes in circumstances indicate that the carrying values may not be recoverable. At each reporting date, an assessment is made for any indication of impairment. If an indication of impairment exists, recoverability is tested by comparing the carrying amount of the asset to the net undiscounted cash flows expected to be generated from the asset. If those net undiscounted cash flows do not exceed the carrying amount (i.e. the asset is not recoverable), the next step would be performed, which is to determine the fair value of the asset and record an impairment charge, if any. Intangible Assets Intangible assets identified on the acquisition of a business are capitalized separately from goodwill if the fair value can be measured reliably on initial recognition (transaction date) and, if they are determined to be finite-lived, are amortized and recorded as operating expenses on a straight-line basis over their useful lives, from two to twelve years, which reflects the pattern in which the economic benefits are realized. Intangible assets consist primarily of mutual fund and other client management contracts, customer relationships and distribution agreements. The company considers its own assumptions, which require management's judgment, about renewal or extension of the term of the arrangement, consistent with its expected use of the asset. A change in the useful life of an intangible asset could have a significant impact on the company's amortization expense. Where evidence exists that the underlying arrangements have a high likelihood of continued renewal at little or no cost to the company, the intangible asset is assigned an indefinite life and reviewed for impairment on an annual basis. The company reevaluates the useful life determination for intangible assets each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life or an indication of impairment. Management contracts that are managed and operated on a single global platform are reviewed in aggregate as one unit of valuation and are considered interchangeable because investors may freely transfer between funds. Similarly, cash flows generated by new funds added to the global platform are included when determining the fair value of the intangible asset. Definite-lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. In addition, management judgment is required to estimate the period over which definite-lived intangible assets will contribute to the company's cash flows and the pattern in which these assets will be consumed. Intangible assets not subject to amortization are tested for impairment annually as of October 1 or more frequently if events or changes in circumstances indicate that the asset might be impaired. The impairment test consists of a comparison of the fair value of an intangible asset with its carrying amount. If the carrying amount of the intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. Fair value is generally determined using an income approach where estimated future cash flows are discounted to arrive at a single present value amount. Goodwill Goodwill represents the excess of cost over the identifiable net assets of businesses acquired and is recorded in the functional currency of the acquired entity. Goodwill is recognized as an asset and is reviewed for impairment annually as of October 1 and between annual tests when events and circumstances indicate that impairment may have occurred. The company has determined that it has one reporting unit for goodwill impairment testing purposes, the consolidated Invesco Ltd. single operating segment, which is consistent with internal management reporting and management's oversight of operations. The company evaluated the components of its business, which are business units one level below the operating segment level in making this determination. The company's operating segment represents one reporting unit because all of the components are similar due to the common nature of products and services offered, type of clients, methods of distribution, manner in which each component is operated, extent to which they share assets and resources, and the extent to which they support and benefit from common product development efforts. Traditional profit and loss measures are not produced and therefore not reviewed by component management for any of the components. Furthermore, the financial informatio

Fair Value Of Assets And Liabil

Fair Value Of Assets And Liabilities	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
FAIR VALUE OF ASSETS AND LIABILITIES	FAIR VALUE OF ASSETS AND LIABILITIES The carrying value and fair value of financial instruments is presented in the below summary table. The fair value of financial instruments held by CIP are presented in Note 19 , "Consolidated Investment Products". December 31, 2017 December 31, 2016 $ in millions Carrying Value Fair Value Carrying Value Fair Value Cash and cash equivalents 2,006.4 2,006.4 1,328.0 1,328.0 Available-for-sale investments 85.2 85.2 154.0 154.0 Trading investments 277.3 277.3 329.6 329.6 Foreign time deposits * 28.6 28.6 26.9 26.9 Assets held for policyholders 12,444.5 12,444.5 8,224.2 8,224.2 Policyholder payables * (12,444.5 ) (12,444.5 ) (8,224.2 ) (8,224.2 ) Put option contracts 0.8 0.8 21.8 21.8 UIT-related financial instruments sold, not yet purchased (1.4 ) (1.4 ) (6.0 ) (6.0 ) Contingent consideration liability (57.4 ) (57.4 ) (78.2 ) (78.2 ) Long-term debt * (2,075.8 ) (2,258.1 ) (2,102.4 ) (2,206.5 ) ____________ * These financial instruments are not measured at fair value on a recurring basis. See the indicated footnotes for additional information about the carrying and fair values of these financial instruments. Foreign time deposits are measured at cost plus accrued interest, which approximates fair value, and are accordingly classified as Level 2 securities. A three-level valuation hierarchy exists for disclosure of fair value measurements based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows: • Level 1 - inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2 - inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 - inputs to the valuation methodology are unobservable and significant to the fair value measurement. An asset or liability's categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. There are three types of valuation approaches: a market approach, which uses observable prices and other relevant information that is generated by market transactions involving identical or comparable assets or liabilities; an income approach, which uses valuation techniques to convert future amounts to a single, discounted present value amount; and a cost approach, which is based on the amount that currently would be required to replace the service capacity of an asset. The following is a description of the valuation methodologies used for assets and liabilities measured at fair value, as well as the general classification of such assets and liabilities pursuant to the valuation hierarchy. Cash equivalents Cash investments in affiliated money market funds are valued under the market approach through the use of quoted market prices in an active market, which is the net asset value of the underlying funds, and are classified within level 1 of the valuation hierarchy. Available-for-sale investments Seed money is valued under the market approach through the use of quoted market prices available in an active market and is classified within level 1 of the valuation hierarchy; there is no modeling or additional information needed to arrive at the fair values of these investments. At December 31, 2017 and December 31, 2016 , investments in CLOs were valued using pricing information obtained by an independent third-party pricing source. Other debt securities are valued using a cost valuation technique due to the lack of available cash flow and market data and are accordingly also classified within level 3 of the valuation hierarchy. Trading investments Trading investments include the following: • Investments related to deferred compensation plans Investments related to deferred compensation plans are valued under the market approach through the use of quoted prices in an active market and are classified within level 1 of the valuation hierarchy. • Seed money Seed money is valued under the market approach through the use of quoted market prices available in an active market and is classified within level 1 of the valuation hierarchy; there is no modeling or additional information needed to arrive at the fair values of these investments. • Other equity securities Other equity securities consist of investments in publicly-traded equity securities. These securities are valued under the market approach through the use of quoted prices on an exchange. To the extent these securities are actively traded, valuation adjustments are not applied and they are categorized within level 1 of the valuation hierarchy; otherwise, they are categorized in level 2. • UIT-related equity and debt securities The company invests in UIT-related equity and debt securities consisting of investments in corporate equities, UITs, and from time-to-time municipal securities. Each is discussed more fully below. Corporate equities The company temporarily holds investments in corporate equities for purposes of creating a UIT. Corporate equities are valued under the market approach through use of quoted prices on an exchange. To the extent these securities are actively traded, valuation adjustments are not applied and they are categorized within level 1 of the valuation hierarchy; otherwise, they are categorized in level 2. UITs The company may hold units of its sponsored UITs at period-end for sale in the primary market or secondary market. Equity UITs are valued under the market approach through use of quoted prices on an exchange. Fixed income UITs are valued using recently executed transaction prices, market price quotations (where observable), bond spreads, or credit default swap spreads. The spread data used is for the same maturities as the underlying bonds. If the spread data does not reference the issuers, then data that references comparable issuers is used. When observable price quotations are not available, fair value is determined based on cash flow models with yield curves, bond or single name credit default spreads, and recovery rates based on collateral value as key inputs. Depending on the nature of the inputs, these investments are categorized as level 1, 2, or 3. Assets held for policyholders Assets held for policyholders are measured at fair value under the market approach based on the quoted prices of the underlying funds in an active market and are classified within level 1 of the valuation hierarchy. The policyholder payables are indexed to the value of the assets held for policyholders and are therefore not included in the tables below. Put option contracts The company has purchased several put option contracts to hedge economically foreign currency risk on the translation of a portion of its Pound Sterling-denominated earnings and Euro-denominated earnings into U.S. Dollars (purchases of $8.1 million and $14.5 million for the years ended December 31, 2017 and December 31, 2016 , respectively). These were the only contracts entered into during the period to hedge economically foreign currency risk for the Pound Sterling-denominated earnings and provide coverage through December 31, 2018 . The economic hedge is predominantly triggered upon the impact of a significant decline in the Pound sterling/U.S. Dollar foreign exchange rate or Euro/U.S. Dollar foreign exchange rate. Open put option contracts are marked-to-market through earnings, which are recorded in the company's Consolidated Statements of Income in other gains and losses. These derivative contracts are valued using option valuation models and are included in other assets in the company's Consolidated Balance Sheets. The significant inputs in these models (volatility, forward points and swap curves) are readily available in public markets or can be derived from observable market transactions for substantially the full terms of the contracts and are classified within level 2 of the valuation hierarchy. The company recognized a loss of $21.0 million in the year ended December 31, 2017 ( gain of $22.0 million in the year ended December 31, 2016 ) related to the change in market value of these put option contracts. In these transactions, the reference rate is an average foreign exchange rate for the applicable time frame. Deferred compensation-related total return swap In addition to holding trading investments, in 2017 the company purchased a total return swap (TRS) to hedge economically certain of these deferred compensation liabilities. The notional value of the total return swap at December 31, 2017 was $108.3 million and its market value was $1.6 million . The market value of the TRS was determined under the market approach using quoted prices of the underlying investments. The TRS is classified as level 2 of the valuation hierarchy. During the year ended December 31, 2017 market valuation gains of $8.8 million were recognized in other gains and losses, net. Contingent Consideration Liability During 2015, the company acquired investment management contracts from Deutsche Bank. Indefinite-lived intangible assets were valued at $119.3 million . This transaction was a non-cash investing activity during the period. The purchase price was comprised solely of contingent consideration payable in future periods, and is linked to future revenues generated from the contracts. The contingent consideration liability was recorded at fair value as of the date of acquisition using a discounted cash flow model, and is categorized within level 3 of the valuation hierarchy. At December 31, 2017 inputs used in the model included assumed growth rates in AUM ranging from (9.2)% to 8.35% (weighted average growth rate of 0.16% ) and a discount rate of 3.89% . Changes in fair value are recorded in Other gains and losses, net in the Consolidated Statements of Income in the period incurred. An increase in AUM levels and a decrease in the discount rate would increase the fair value of the contingent consideration liability while a decrease in forecasted AUM and an increase in the discount rate would decrease the liability. The following table presents, for each of the hierarchy levels described above, the carrying value of the company's assets and liabilities, including major security type for equity and debt securities, which are measured at fair value on the company's Consolidated Balance Sheet as of December 31, 2017 : As of December 31, 2017 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds 875.5 875.5 — — Investments:* Available-for-sale: Seed money 69.3 69.3 — — CLOs 6.0 — 6.0 — Other debt securities 9.9 — — 9.9 Trading investments: Investments related to deferred compensation plans 92.3 92.3 — — Seed money 173.7 173.7 — — Other equity securities 8.9 8.9 — — UIT-related equity and debt securities: Corporate equities 2.0 2.0 — — UITs 0.4 0.4 — — Assets held for policyholders 12,444.5 12,444.5 — — Put option contracts 0.8 — 0.8 — Total 13,683.3 13,666.6 6.8 9.9 Liabilities: UIT-related financial instruments sold, not yet purchased: Exchange traded funds (1.4 ) (1.4 ) — — Contingent consideration liability (57.4 ) — — (57.4 ) Total (58.8 ) (1.4 ) — (57.4 ) ____________ * Foreign time deposits of $28.6 million are excluded from this table. Equity and other investments of $277.3 million and $6.2 million , respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards. The following table presents, for each of the hierarchy levels described above, the carrying value of the company's assets and liabilities, including major security type for equity and debt securities, which are measured at fair value on the company's Consolidated Balance Sheet as of December 31, 2016 : As of December 31, 2016 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Assets: Cash equivalents: Money market funds 476.2 476.2 — — Investments:* Available-for-sale: Seed money 127.9 127.9 — — CLOs 12.9 — — 12.9 Other debt securities 13.2 — — 13.2 Trading investments: Investments related to deferred compensation plans 170.5 170.5 — — Seed money 121.9 121.9 — — Other equity securities 30.4 30.4 — — UIT-related equity and debt securities: Corporate equities 1.2 1.2 — — UITs 5.6 5.6 — — Assets held for policyholders 8,224.2 8,224.2 — — Put option contracts 21.8 — 21.8 — Total 9,205.8 9,157.9 21.8 26.1 Liabilities: UIT-related financial instruments sold, not yet purchased: Exchange traded funds (5.2 ) (5.2 ) — — U.S. treasury securities (0.8 ) (0.8 ) — — Contingent consideration liability (78.2 ) — — (78.2 ) Total (84.2 ) (6.0 ) — (78.2 ) ____________ * Foreign time deposits of $26.9 million are excluded from this table. Equity and other investments of $279 million and $5.8 million , respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards. The following table shows a reconciliation of the beginning and ending fair value measurements for level 3 assets and liabilities during the year ended December 31, 2017 and December 31, 2016 , which are valued using significant unobservable inputs: For the year ended December 31, 2017 For the year ended December 31, 2016 $ in millions Contingent Consideration Liability CLOs Other Debt Securities Contingent Consideration Liability CLOs Other Debt Securities Beginning balance (78.2 ) 12.9 13.2 (83.9 ) 1.4 5.9 Adjustment for adoption of ASU 2015-02 — — — — 11.5 — Beginning balance, as adjusted (78.2 ) 12.9 13.2 (83.9 ) 12.9 5.9 Purchases/acquisitions — — 7.4 — — 21.4 Returns of capital — — — — (3.0 ) — Net unrealized gains and losses included in other gains and losses* 7.6 — (3.2 ) (7.4 ) — — Net unrealized gains and losses included in accumulated other comprehensive income/(loss) * — — — — 3.0 — Disposition/settlements 13.2 — (7.5 ) 13.1 — (14.1 ) Transfer from level 3 to level 2 — (12.9 ) — — — — Ending balance (57.4 ) — 9.9 (78.2 ) 12.9 13.2 ____________ * These unrealized gains and losses are attributable to balances still held at the respective year ends.

Investments

Investments	12 Months Ended
	Dec. 31, 2017
Investments [Abstract]
INVESTMENTS	INVESTMENTS The disclosures below include details of the company's investments. Investments held by CIP are detailed in Note 19 , "Consolidated Investment Products." $ in millions December 31, 2017 December 31, 2016 Available-for-sale investments: Seed money 69.3 127.9 CLOs 6.0 12.9 Other debt securities 9.9 13.2 Trading investments: Investments related to deferred compensation plans 92.3 170.5 Seed money 173.7 121.9 UIT-related equity and debt securities 2.4 6.8 Other equity securities 8.9 30.4 Equity method investments 277.3 279.0 Foreign time deposits 28.6 26.9 Other 6.2 5.8 Total investments 674.6 795.3 Available for sale investments Realized gains and losses recognized in the Consolidated Statements of Income during the year from investments classified as available-for-sale are as follows: 2017 2016 2015 $ in millions Proceeds from Sales Gross Realized Gains Gross Realized Losses Proceeds from Sales Gross Realized Gains Gross Realized Losses Proceeds from Sales Gross Realized Gains Gross Realized Losses Seed money 62.5 4.3 (1.5 ) 42.7 1.5 (1.6 ) 48.1 2.2 (0.2 ) CLOs 7.1 1.9 — 3.0 — — 2.6 0.5 — Other debt securities 9.9 2.5 — 13.6 — (0.5 ) 0.4 — — 79.5 8.7 (1.5 ) 59.3 1.5 (2.1 ) 51.1 2.7 (0.2 ) Upon the sale of available-for-sale securities, net realized gains of $7.2 million , were transferred from accumulated other comprehensive income into the Consolidated Statements of Income during the year ended December 31, 2017 (year ended December 31, 2016 : $0.6 million net losses, year ended December 31, 2015 : $2.5 million net gains). The specific identification method is used to determine the realized gain or loss on securities sold or otherwise disposed. Gross unrealized holding gains and losses recognized in other accumulated comprehensive income from available-for-sale investments are presented in the table below: December 31, 2017 December 31, 2016 $ in millions Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Seed money 65.1 5.5 (1.3 ) 69.3 127.2 6.8 (6.1 ) 127.9 CLOs 4.9 1.1 — 6.0 9.2 3.7 — 12.9 Other debt securities 9.9 — — 9.9 13.2 — — 13.2 79.9 6.6 (1.3 ) 85.2 149.6 10.5 (6.1 ) 154.0 At December 31, 2017 , 50 seed money funds ( December 31, 2016 : 103 seed money funds) experienced gross unrealized holding losses. The following table provides a breakdown of the unrealized losses. December 31, 2017 December 31, 2016 $ in millions Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Less than 12 months 9.4 (0.8 ) 1.9 (0.2 ) 12 months or greater 15.0 (0.5 ) 56.4 (5.9 ) Total 24.4 (1.3 ) 58.3 (6.1 ) The company has reviewed investment securities for other-than-temporary impairment (OTTI) in accordance with its accounting policy and has recognized $3.2 million other-than-temporary impairment charges on certain available-for-sale investments during the year ended December 31, 2017 (year ended December 31, 2016 : none ). In contemplation of OTTI, the company conducts a review of the financial condition and near-term prospects of the underlying securities as well as the severity and duration of any declines in fair value. No OTTI is recorded for seeded funds which are expected to recover their value over time and for which the company has the intent and ability to hold the securities until this recovery occurs. For CLO investments, the company reviewed the estimated future cashflows of each CLO. If the present value of the estimated future cashflows is lower than the carrying value of the investment and there is an adverse change in estimated cashflows, the impairment is considered to be other than temporary. During the year ended December 31, 2017 and 2016 , no such other-than-temporary impairment was recognized. Available-for-sale debt securities as of December 31, 2017 by maturity, are set out below: Available-for-Sale (Fair Value) Less than one year 9.9 One to five years 2.8 Five to ten years 3.2 Greater than ten years — Total available-for-sale 15.9 Trading investments Net gains recorded in Other gains/(losses) in the Consolidated Statements of Income resulting from trading investments for the year ended December 31, 2017 , were $40.4 million ( December 31, 2016 : $14.2 million gain). The portion of trading gains and losses for the year ended December 31, 2017 , that relates to trading securities still held at December 31, 2017 , was a $18.9 million net gain ( December 31, 2016 : $16.9 million net gain ). Equity method investments Following are the company's investments in joint ventures and affiliates, which are accounted for using the equity method and are recorded as investments on the Consolidated Balance Sheets: Name of Company Country of Incorporation % Voting Interest Owned Huaneng Invesco WLR (Beijing) Investment Fund Management Company Ltd. China 50.0% Invesco Great Wall Fund Management Company Limited China 49.0% Pocztylion - ARKA Poland 29.3% Undistributed earnings from equity method investees have not been a material restriction on the company's ability to pay dividends to shareholders. Equity method investments also include the company's investments in certain of its managed private equity, real estate and other investment entities. The company's investment is generally less than 5% of the capital of these entities. These entities include variable interest entities for which the company has determined that it is not the primary beneficiary and other investment products structured as partnerships for which the company is the general partner and the other limited partners possess either substantive kick-out, liquidation or participation rights. See Note 1 , “Accounting Policies,” for additional information. Noncontrolling interests in consolidated entities The company owns 100% of the voting control of its subsidiary entities, directly or indirectly, with the exception of the following entities, which are consolidated with resulting noncontrolling interests: Name of Company Country of Incorporation % Voting Interest Owned VV Immobilien Verwaltungs und Beteiligungs GmbH Germany 70.0% VV Immobilien Verwaltungs GmbH Germany 70.0% HVH Immobilien und Beteiligungs GmbH Germany 70.0%

Property, Equipment And Softwar

Property, Equipment And Software	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
PROPERTY, EQUIPMENT AND SOFTWARE	PROPERTY, EQUIPMENT AND SOFTWARE The following is a summary of property, equipment and software: $ in millions December 31, 2017 December 31, 2016 Technology and Other Equipment 261.0 242.3 Software 621.9 467.4 Land and Buildings 87.5 68.2 Leasehold Improvements 204.4 210.9 Work in Process 44.8 117.0 Property, Equipment and Software, Gross 1,219.6 1,105.8 Less: Accumulated Depreciation (728.9 ) (641.1 ) Property, Equipment and Software, Net 490.7 464.7 Depreciation expense related to property, equipment and software was $99.4 million , $87.3 million and $83.0 million for the years ended December 31, 2017 , 2016 and 2015 , respectively.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2017
Intangible Assets, Net (Excluding Goodwill) [Abstract]
INTANGIBLE ASSETS	INTANGIBLE ASSETS The following table presents the major classes of the company's intangible assets at December 31 , 2017 and 2016 : $ in millions Gross Book Value Accumulated Amortization Net Book Value December 31, 2017 Management contracts - indefinite-lived 1,523.3 N/A 1,523.3 Management contracts - finite-lived 68.8 (66.3 ) 2.5 Customer relationships 40.0 (25.3 ) 14.7 Other 27.6 (9.4 ) 18.2 Total 1,659.7 (101.0 ) 1,558.7 December 31, 2016 Management contracts - indefinite-lived 1,363.6 N/A 1,363.6 Management contracts - finite-lived 67.7 (56.6 ) 11.1 Customer relationships 40.0 (21.9 ) 18.1 Other 9.8 (3.2 ) 6.6 Total 1,481.1 (81.7 ) 1,399.4 On August 18, 2017, Invesco acquired $167.1 million in management contracts and technology related intangible assets as part of the acquisition of the European ETF business (2016: $63.4 million related to the purchases of Jemstep and the remaining interest in our Indian joint venture). Amortizable intangible assets of $16.9 million related to 2017 acquisitions have a weighted-average amortization period of 1.9 years (2016 acquisitions: $9.8 million have a weighted-average amortization period of 1.1 years ). The 2017 and 2016 annual impairment reviews of indefinite-lived intangible assets determined that no impairment existed at the respective review dates. Amortization expense was $17.4 million during the year ended December 31, 2017 ( December 31, 2016 : $13.9 million ; December 31, 2015 : $10.6 million ) and is included within General and administrative expenses in the Consolidated Statements of Income. Estimated amortization expense for each of the five succeeding fiscal years based upon the company's intangible assets at December 31, 2017 is as follows: $ in millions Years Ended December 31, Estimated Amortization Expense 2018 15.6 2019 8.1 2020 4.7 2021 4.7 2022 2.3

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2017
Goodwill [Abstract]
GOODWILL	GOODWILL The table below details changes in the goodwill balance: $ in millions Net Book Value January 1, 2017 6,129.2 Business combinations 193.3 Foreign exchange 268.2 December 31, 2017 6,590.7 January 1, 2016 6,175.7 Business combinations 135.7 Foreign exchange (182.2 ) December 31, 2016 6,129.2 The 2017 addition to goodwill consists of $193.3 million related to the preliminary valuation of the acquisition of the European ETF business. The 2016 addition to goodwill consists of $135.7 million related to the the acquisitions of our Indian asset management company and Jemstep. The 2017 and 2016 annual impairment reviews determined that no impairment existed at the respective review dates. No interim impairment tests were deemed necessary during 2017 or 2016 .

Other Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
OTHER LIABILITIES	OTHER LIABILITIES The table below details the components of other liabilities: As of $ in millions December 31, 2017 December 31, 2016 Compensation and benefits 101.2 92.8 Accrued bonus and deferred compensation 594.9 561.5 Accrued compensation and benefits 696.1 654.3 Accruals and other liabilities 302.3 280.6 Deferred carried interest 60.4 87.7 Contingent consideration liability 57.4 78.2 Accounts payable 320.1 274.3 Income taxes payable 155.5 91.6 Accounts payable and accrued expenses 895.7 812.4

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT The issuer of the senior notes is an indirect 100% owned finance subsidiary of Invesco Ltd. (the Parent), and the Parent fully and unconditionally guaranteed the securities . As discussed in Note 1, "Accounting Policies - Cash and cash equivalents," certain of our subsidiaries are required to maintain minimum levels of capital. These and other similar provisions of applicable law may have the effect of limiting withdrawals of capital, repayment of intercompany loans and payment of dividends by such entities. The disclosures below include details of the company's debt. Debt of CIP is detailed in Note 19 , “Consolidated Investment Products.” December 31, 2017 December 31, 2016 $ in millions Carrying Value** Fair Value Carrying Value** Fair Value Floating rate credit facility expiring August 11, 2022 — — 28.7 28.7 Unsecured Senior Notes*: $600 million 3.125% - due November 30, 2022 596.9 608.8 596.3 604.7 $600 million 4.000% - due January 30, 2024 594.0 634.7 593.2 625.3 $500 million 3.750% - due January 15, 2026 495.1 515.0 494.5 506.4 $400 million 5.375% - due November 30, 2043 389.8 499.6 389.7 441.4 Long-term debt 2,075.8 2,258.1 2,102.4 2,206.5 ____________ * The company's senior note indentures contain certain restrictions on mergers or consolidations. Beyond these items, there are no other restrictive covenants in the indentures. ** The difference between the principal amounts and the carrying values of the senior notes in the table above reflect the unamortized debt issuance costs and discounts. The fair market value of the company's senior notes was determined by market quotes provided by Bloomberg, which is considered a Level 2 valuation input. In the absence of an active market, the company relies upon the average price quoted by brokers for determining the fair market value of the debt. Analysis of Borrowings by Maturity: $ in millions December 31, 2017 2022 596.9 2024 594.0 2026 495.1 2043 389.8 Long-term debt 2,075.8 On August 11, 2017 the company amended and restated the credit facility agreement increasing the borrowing limit to $1.5 billion and extending the expiration date to August 11, 2022 . At December 31, 2017 , the outstanding balance on the credit facility was zero . Borrowings under the credit facility will bear interest at (i) LIBOR for specified interest periods or (ii) a floating base rate (based upon the highest of (a) the Bank of America prime rate, (b) the Federal Funds rate plus 0.50% and (c) LIBOR for an interest period of one month plus 1.00% ), plus, in either case, an applicable margin determined with reference to the higher of the available credit ratings of the company or its indirect subsidiary Invesco Finance PLC. Based on credit ratings as of December 31, 2017 of the company, the applicable margin for LIBOR-based loans was 1.00% and for base rate loans was 0.00% . In addition, the company is required to pay the lenders a facility fee on the aggregate commitments of the lenders (whether or not used) at a rate per annum which is based on the higher of the available credit ratings of company or its indirect subsidiary Invesco Finance PLC. Based on credit ratings as of December 31, 2017 , the annual facility fee was equal to 0.125% . The credit agreement governing the credit facility contains customary restrictive covenants on the company and its subsidiaries. Restrictive covenants in the credit agreement include, but are not limited to: prohibitions on creating, incurring or assuming any liens; entering into merger arrangements; selling, leasing, transferring or otherwise disposing of assets; making a material change in the nature of the business; making a significant accounting policy change in certain situations; entering into transactions with affiliates; and incurring indebtedness through the subsidiaries (other than the borrower, Invesco Finance PLC). Many of these restrictions are subject to certain minimum thresholds and exceptions. Financial covenants under the credit agreement include: (i) the quarterly maintenance of a debt/EBITDA leverage ratio, as defined in the credit agreement, of not greater than 3.25 : 1.00 , (ii) a coverage ratio (EBITDA, as defined in the credit agreement/interest payable for the four consecutive fiscal quarters ended before the date of determination) of not less than 4.00 : 1.00 . The credit agreement governing the credit facility also contains customary provisions regarding events of default which could result in an acceleration or increase in amounts due, including (subject to certain materiality thresholds and grace periods) payment default, failure to comply with covenants, material inaccuracy of representation or warranty, bankruptcy or insolvency proceedings, change of control, certain judgments, ERISA matters, cross-default to other debt agreements, governmental action prohibiting or restricting the company or its subsidiaries in a manner that has a material adverse effect and failure of certain guaranty obligations. The company is in compliance with all regulatory minimum net capital requirements. The lenders (and their respective affiliates) may have provided, and may in the future provide, investment banking, cash management, underwriting, lending, commercial banking, leasing, foreign exchange, trust or other advisory services to the company and its subsidiaries and affiliates. These parties may have received, and may in the future receive, customary compensation for these services. At December 31, 2017 , the company maintains approximately $10.6 million in letters of credit from a variety of banks. The letters of credit are generally one-year automatically-renewable facilities and are maintained for various commercial reasons.

Share Capital

Share Capital	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
SHARE CAPITAL	SHARE CAPITAL The number of common shares and common share equivalents issued are represented in the table below: In millions December 31, 2017 December 31, 2016 December 31, 2015 Common shares issued 490.4 490.4 490.4 Less: Treasury shares for which dividend and voting rights do not apply (83.3 ) (86.6 ) (72.9 ) Common shares outstanding 407.1 403.8 417.5 The company did not purchase shares in the open market during the twelve months ended December 31, 2017 (year ended December 31, 2016 : 18.1 million shares at a cost of $535.0 million ). Separately, an aggregate of 1.9 million shares were withheld on vesting events during the year ended December 31, 2017 to meet employees' withholding tax obligations ( December 31, 2016 : 1.5 million ). The fair value of these shares withheld at the respective withholding dates was $63.8 million ( December 31, 2016 : $42.0 million ). At December 31, 2017 , approximately $1,643.0 million remained authorized under the company's share repurchase authorizations approved by the Board on October 11, 2013 and July 22, 2016 ( December 31, 2016 : $1,643.0 million ). Total treasury shares at December 31, 2017 were 92.4 million ( December 31, 2016 : 95.9 million ), including 9.1 million unvested restricted stock awards ( December 31, 2016 : 9.3 million ) for which dividend and voting rights apply. The market price of common shares at the end of 2017 was $36.54 . The total market value of the company's 92.4 million treasury shares was $3.4 billion at December 31, 2017 . Movements in Treasury Shares comprise: Year ended In millions December 31, 2017 December 31, 2016 December 31, 2015 Beginning balance 95.9 81.3 69.4 Acquisition of common shares 1.9 19.6 17.4 Distribution of common shares (5.2 ) (4.7 ) (5.2 ) Common shares distributed to meet ESPP obligation (0.2 ) (0.3 ) (0.1 ) Common shares distributed to meet option exercises — — (0.2 ) Ending balance 92.4 95.9 81.3

Other Comprehensive Income_(Los

Other Comprehensive Income/(Loss)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
OTHER COMPREHENSIVE INCOME/(LOSS)	OTHER COMPREHENSIVE INCOME/(LOSS) The components of accumulated other comprehensive income/(loss) were as follows: 2017 $ in millions Foreign currency translation Employee benefit plans Equity method investments Available-for-sale investments Total Other comprehensive income/(loss), net of tax: Currency translation differences on investments in foreign subsidiaries 389.4 — — — 389.4 Actuarial gain/(loss) related to employee benefit plans — 21.1 — — 21.1 Settlement related to employee benefit plans — 5.9 — — 5.9 Reclassification of actuarial (gains)/losses into employee compensation expenses — 2.5 — — 2.5 Share of other comprehensive income/(loss) of equity method investments — — (0.5 ) — (0.5 ) Unrealized gains/(losses) on available-for-sale investments — — — 5.1 5.1 Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses, net — — — (5.4 ) (5.4 ) Other comprehensive income/(loss) 389.4 29.5 (0.5 ) (0.3 ) 418.1 Beginning balance (679.9 ) (139.2 ) 4.8 5.0 (809.3 ) Other comprehensive income/(loss) 389.4 29.5 (0.5 ) (0.3 ) 418.1 Ending balance (290.5 ) (109.7 ) 4.3 4.7 (391.2 ) 2016 $ in millions Foreign currency translation Employee benefit plans Equity method investments Available-for-sale investments Total Other comprehensive income/(loss) net of tax: Currency translation differences on investments in foreign subsidiaries (314.1 ) — — — (314.1 ) Actuarial gain/(loss) related to employee benefit plans — (39.5 ) — — (39.5 ) Prior service credit related to employee benefit plans — (3.1 ) — — (3.1 ) Settlement related to employee benefit plans — (5.5 ) — — (5.5 ) Reclassification of prior service (credit)/cost into employee compensation expense — (7.0 ) — — (7.0 ) Reclassification of actuarial (gains)/losses into employee compensation expenses — 1.5 — — 1.5 Share of other comprehensive income/(loss) of equity method investments — — (1.1 ) — (1.1 ) Unrealized gains/(losses) on available-for-sale investments — — — 5.2 5.2 Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses, net — — — 0.3 0.3 Other comprehensive income/(loss) (314.1 ) (53.6 ) (1.1 ) 5.5 (363.3 ) Beginning balance (365.8 ) (85.6 ) 5.9 (0.5 ) (446.0 ) Other comprehensive income/(loss) (314.1 ) (53.6 ) (1.1 ) 5.5 (363.3 ) Ending balance (679.9 ) (139.2 ) 4.8 5.0 (809.3 ) 2015 $ in millions Foreign currency translation Employee benefit plans Equity method investments Available-for-sale investments Total Other comprehensive income/(loss) net of tax: Currency translation differences on investments in foreign subsidiaries (493.9 ) — — — (493.9 ) Actuarial gain/(loss) related to employee benefit plans — 11.1 — — 11.1 Reclassification of prior service (credit)/cost into employee compensation expense — (7.2 ) — — (7.2 ) Reclassification of actuarial (gains)/losses into employee compensation expenses — 2.2 — — 2.2 Share of other comprehensive income/(loss) of equity method investments — — (0.6 ) — (0.6 ) Unrealized gains/(losses) on available-for-sale investments — — — (6.0 ) (6.0 ) Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses, net — — — (0.4 ) (0.4 ) Other comprehensive income/(loss) (493.9 ) 6.1 (0.6 ) (6.4 ) (494.8 ) Beginning balance 128.1 (91.7 ) 6.5 5.9 48.8 Other comprehensive income/(loss) (493.9 ) 6.1 (0.6 ) (6.4 ) (494.8 ) Ending balance (365.8 ) (85.6 ) 5.9 (0.5 ) (446.0 ) Net Investment Hedge During the second quarter of 2016 , the Company designated certain intercompany debt as a non-derivative net investment hedging instrument against foreign currency exposure related to its net investment in foreign operations. At December 31, 2017 , £130 million ( $175.9 million ) of intercompany debt was designated as a net investment hedge. For the twelve months ended December 31, 2017 , the Company recognized foreign currency losses of $15.3 million resulting from the net investment hedge within currency translation differences on investments in foreign subsidiaries in other comprehensive income. No hedge ineffectiveness was recognized in income.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION The company recognized total expenses of $175.3 million , $159.7 million and $150.3 million related to equity-settled share-based payment transactions in 2017 , 2016 and 2015 , respectively. The total income tax benefit recognized in the Consolidated Statements of Income for share-based compensation arrangements was $48.9 million for 2017 ( 2016 : $44.7 million ; 2015 : $43.8 million ). Share awards are broadly classified into two categories: time-vested and performance-vested. Share awards are measured at fair value at the date of grant and are expensed, based on the company's estimate of shares that will eventually vest, on a straight-line or accelerated basis over the vesting period. Time-vested awards vest ratably over or cliff-vest at the end of a period of continued employee service. Performance-vested awards cliff-vest at the end of or vest ratably over a defined vesting period of continued employee service upon the company's attainment of certain performance criteria. Time-vested and performance-vested share awards are granted in the form of restricted share awards (RSAs) or restricted share units (RSUs). Performance-vested awards are tied to the achievement of specified levels of adjusted diluted earnings per share and adjusted operating margin. In the event that either targeted financial measure is achieved at or above a vesting threshold for a particular performance measurement period, the portion of the performance-vested award subject to targeted financial measures will vest proportionately between 0% and 100% based upon the higher achieved level for that year. With respect to time-vested awards, dividends accrue directly to the employee holder of RSAs, and cash payments in lieu of dividends are made to employee holders of certain RSUs. With respect to performance-vested awards, dividends and cash payments in lieu of dividends are deferred and are paid at the same rate as on our shares if and to the extent the award vests. In May 2016, the company's shareholders approved the 2016 Global Equity Incentive Plan (2016 GEIP), which authorized the issuance of up to 21.7 million shares under this plan. The 2011 Global Equity Incentive Plan and the 2008 Global Equity Incentive Plan are predecessor plans to the 2016 GEIP. Although there are outstanding awards under the 2011 and 2008 plans, no further grants may be made under such plans. In May 2010, the board approved the 2010 Global Equity Incentive Plan (ST), which authorized the issuance of up to 3 million shares under this plan. With respect to the 2010 Global Equity Incentive Plan (ST), shares are issued only as employment inducement awards in connection with a strategic transaction and, as a result, do not require shareholder approval under the rules of the New York Stock Exchange or otherwise. Movements on share awards priced in U.S. Dollars during the years ended December 31, are detailed below: 2017 2016 2015 Millions of shares, except fair values Time-Vested Performance-Vested Weighted Average Grant Date Fair Value ($) Time-Vested Performance-Vested Time- Vested Performance-Vested Unvested at the beginning of year 12.1 0.8 31.22 10.4 0.6 11.5 0.5 Granted during the year 5.3 0.3 32.23 6.5 0.4 4.1 0.3 Forfeited during the year (0.4 ) — 31.51 (0.3 ) — (0.2 ) — Vested and distributed during the year (5.0 ) (0.2 ) 31.53 (4.5 ) (0.2 ) (5.0 ) (0.2 ) Unvested at the end of the year 12.0 0.9 31.52 12.1 0.8 10.4 0.6 The total fair value of shares that vested during 2017 was $168.7 million ( 2016 : $128.4 million ; 2015 : $202.6 million ). The weighted average grant date fair value of the U.S. dollar share awards that were granted during 2017 was $32.23 ( 2016 : $27.44 ; 2015 : $39.99 ). At December 31, 2017 , there was $264.1 million of total unrecognized compensation cost related to non-vested share awards; that cost is expected to be recognized over a weighted average period of 2.43 years. Employee Stock Purchase Plan (ESPP) The company operates a nonqualified, broad-based ESPP for all eligible employees. Employees may purchase shares of our common stock generally in annual intervals at 85% of fair market value. Employee ESPP contributions may not exceed $6,000 per offering period. Upon the plan vesting date, the company either issues new shares or can utilize shares held in treasury (see Note 9 , "Share Capital") to satisfy the exercise. For the year ended December 31, 2017 , the company recognized $0.9 million in compensation expense related to the employee stock purchase plan ( December 31, 2016 : $0.9 million , December 31, 2015 : $0.9 million ).

Retirement Benefit Plans

Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2017
Retirement Benefits, Description [Abstract]
RETIREMENT BENEFIT PLANS	RETIREMENT BENEFIT PLANS Defined Contribution Plans The company operates defined contribution retirement benefit plans for all qualifying employees. The assets of the plans are held separately from those of the company in funds under the control of trustees. When employees leave the plans prior to vesting fully in the contributions, the contributions payable by the company are reduced by the amount of forfeited contributions. The total amounts charged to the Consolidated Statements of Income for the year ended December 31, 2017 , of $73.1 million ( December 31, 2016 : $58.6 million , December 31, 2015 : $58.4 million ) represent contributions paid or payable to these plans by the company at rates specified in the rules of the plans. As of December 31, 2017 , accrued contributions of $26.2 million ( December 31, 2016 : $23.1 million ) for the current year will be paid to the plans. Defined Benefit Plans The company maintains legacy defined benefit pension plans for qualifying employees of its subsidiaries in the U.K., Ireland, Germany and Taiwan. All defined benefit plans are closed to new participants. In December 2016, the company amended the U.K. plan resulting in a curtailment gain and a prior service cost which were recorded in Other comprehensive income/(loss), net of tax. During 2017 , the company recorded $7.3 million expense related to a partial settlement of the U.K. pension plan. The company also offered a postretirement medical plan in the U.S., which was closed to new participants in 2005. In 2006, the plan was amended to eliminate benefits for all participants who did not meet retirement eligibility by 2008. In November 2014, Invesco further amended the plan, which resulted in its termination and settlement effective December 31, 2016. The assets of all defined benefit schemes are held in separate trustee-administered funds. The most recent actuarial valuations of plan assets and the present value of the defined benefit obligation were valued as of December 31, 2017 . The benefit obligation, related current service cost and prior service cost were measured using the projected unit credit method. Benefit Obligations and Funded Status The amounts included in the Consolidated Balance Sheets arising from the company's obligations and plan assets in respect of its defined benefit retirement plans are as follows: Retirement Plans $ in millions 2017 2016 Benefit obligation (548.6 ) (521.2 ) Fair value of plan assets 486.9 424.1 Funded status (61.7 ) (97.1 ) Amounts recognized in the Consolidated Balance Sheets: Other assets 3.6 3.4 Accrued compensation and benefits (65.3 ) (100.5 ) Funded status (61.7 ) (97.1 ) Changes in the benefit obligations were as follows: Retirement Plans $ in millions 2017 2016 January 1 521.2 490.7 Service cost 2.3 4.6 Interest cost 14.1 16.5 Actuarial (gains)/losses 3.3 102.4 Exchange difference 51.7 (73.5 ) Benefits paid (9.0 ) (13.8 ) Plan amendments — 4.1 Curtailment — (9.8 ) Settlement (35.0 ) — December 31 548.6 521.2 Key assumptions used in plan valuations are detailed below. Appropriate local mortality tables are also used. The weighted average assumptions used to determine defined benefit obligations at December 31 , 2017 , and 2016 are as follows: Retirement Plans 2017 2016 Discount rate 2.47 % 2.64 % Expected rate of salary increases 3.26 % 3.26 % Future pension trend rate increases 2.97 % 2.98 % Changes in the fair value of plan assets in the current period were as follows: Retirement Plans $ in millions 2017 2016 January 1 424.1 422.7 Actual return on plan assets 52.3 71.0 Exchange difference 41.9 (69.9 ) Contributions from the company 11.8 14.2 Benefits paid (9.0 ) (13.9 ) Settlement and other (34.2 ) — December 31 486.9 424.1 The components of the amount recognized in accumulated other comprehensive income at December 31 , 2017 , and 2016 are as follows: Retirement Plans $ in millions 2017 2016 Prior service cost/(credit) 3.9 3.7 Net actuarial loss/(gain) 128.3 164.1 Total 132.2 167.8 The amounts in accumulated other comprehensive income expected to be amortized into the Consolidated Income Statement during the year ending December 31 , 2018 are as follows: $ in millions Retirement Plans Prior service cost/(credit) 0.1 Net actuarial loss/(gain) 2.4 Total 2.5 The total accumulated benefit obligation and fair value of plan assets for plans with accumulated benefit obligations in excess of plan assets and the projected benefit obligation and fair value of plan assets for pension plans with projected benefit obligations in excess of plan assets are as follows: Retirement Plans $ in millions 2017 2016 Plans with accumulated benefit obligation in excess of plan assets: Accumulated benefit obligation 539.4 512.1 Fair value of plan assets 474.1 411.6 Plans with projected benefit obligation in excess of plan assets: Projected benefit obligation 539.4 512.1 Fair value of plan assets 474.1 411.6 Net Periodic Benefit Cost The components of net periodic benefit cost in respect of these defined benefit plans are as follows: Retirement Plans Medical Plan $ in millions 2017 2016 2015 2016 2015 Service cost 2.3 4.6 5.4 — — Interest cost 14.1 16.5 17.7 — — Expected return on plan assets (22.6 ) (21.7 ) (22.9 ) — — Amortization of prior service cost/(credit) 0.2 — 0.1 (11.3 ) (11.3 ) Amortization of net actuarial (gain)/loss 3.0 1.8 3.0 (0.3 ) (0.3 ) Settlement 7.3 — — (9.0 ) — Net periodic benefit cost/(credit) 4.3 1.2 3.3 (20.6 ) (11.6 ) The weighted average assumptions used to determine net periodic benefit cost for the years ended December 31 , 2017 , 2016 , and 2015 are: Retirement Plans 2017 2016 2015 Discount rate 2.64 % 3.69 % 3.52 % Expected return on plan assets 5.01 % 5.53 % 5.90 % Expected rate of salary increases 3.26 % 3.16 % 3.06 % Future pension rate increases 2.98 % 2.98 % 2.88 % In developing the expected rate of return, the company considers long-term compound annualized returns based on historical and current market data. Using this reference information, the company develops forward-looking return expectations for each asset category and an expected long-term rate of return for a targeted portfolio. Discount rate assumptions were based upon AA-rated corporate bonds of suitable terms and currencies. Plan Assets The analysis of the plan assets as of December 31, 2017 was as follows: $ in millions Retirement Plans % of Plan Assets Cash and cash equivalents 10.7 2.2 % Fund investments 227.9 46.8 % Equity securities 133.9 27.5 % Government debt securities 20.9 4.3 % Other assets 13.4 2.8 % Guaranteed investments contracts 80.1 16.5 % Total 486.9 100.0 % The analysis of the plan assets as of December 31, 2016 was as follows: $ in millions Retirement Plans % of Plan Assets Cash and cash equivalents 3.9 0.9 % Fund investments 207.4 48.9 % Equity securities 122.1 28.8 % Government debt securities 73.0 17.2 % Other assets 7.3 1.7 % Guaranteed investments contracts 10.4 2.5 % Total 424.1 100.0 % Plan assets are not held in company stock. The investment policies and strategies for plan assets held by defined benefit plans include: • Funding - to have sufficient assets available to pay members benefits; • Security - to maintain the minimum Funding Requirement; • Stability - to have due regard to the employer's ability in meeting contribution payments given their size and incidence. Fund investments are primarily held in equity and fixed income strategies. The following table presents the carrying value of the plan assets, including major security type for equity and debt securities, which are measured at fair value as of December 31, 2017 : As of December 31, 2017 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and cash equivalents 10.7 10.7 — — Fund investments 227.9 227.9 — — Equity securities 133.9 133.9 — — Government debt securities 20.9 13.9 7.0 — Other assets 80.1 80.1 — — Guaranteed investments contracts 13.4 — — 13.4 Total 486.9 466.5 7.0 13.4 The following table presents the carrying value of the plan assets, including major security type for equity and debt securities, which are measured at fair value as of December 31, 2016 : As of December 31, 2016 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and cash equivalents 3.9 3.9 — — Fund investments 207.4 207.4 — — Equity securities 122.1 122.1 — — Government debt securities 73.0 13.7 59.3 — Other assets 7.3 7.3 — — Guaranteed investment contracts 10.4 — — 10.4 Total 424.1 354.4 59.3 10.4 The following is a description of the valuation methodologies used for each major category of plan assets measured at fair value. Information about the valuation hierarchy levels used to measure fair value is detailed in Note 2 , “Fair Value of Assets and Liabilities.” Cash and cash equivalents Cash equivalents include cash in the bank and cash investments in money market funds. Cash investments in money market funds are valued under the market approach through the use of quoted market prices in an active market, which is the net asset value of the underlying funds, and are classified within level 1 of the valuation hierarchy. Fund investments These plan assets are primarily invested in affiliated funds and are classified within level 1 of the valuation hierarchy. They are valued at the net asset value of shares held by the plan at year end. Equity securities, corporate debt securities and other investments These plan assets are classified within level 1 of the valuation hierarchy and are valued at the closing price reported on the active market on which the individual securities are traded. Government debt securities Government debt securities that have a readily available market price are classified within level 1 of the valuation hierarchy. These securities are valued at the closing price reported on the active market on which the individual securities are traded. Government debt securities that include index-linked bonds are classified within level 2 of the valuation hierarchy. Prices for these bonds are calculated using the relevant index ratio. Guaranteed investment contracts These plan assets are classified within level 3 of the valuation hierarchy and are valued through use of unobservable inputs by discounting the related cash flows based on current yields of similar instruments with comparable durations considering the credit-worthiness of the issuer. Guaranteed investment contracts balance at December 31, 2017 is $13.4 million compared to $10.4 million at December 31, 2016 . Cash Flows The estimated amounts of contributions expected to be paid to the plans during 2018 are $24.5 million for retirement plans. There are no future annual benefits of plan participants covered by insurance contracts issued by the employer or related parties. The benefits expected to be paid in each of the next five fiscal years and in the five fiscal years thereafter are as follows: $ in millions Retirement Plans Expected benefit payments: 2018 9.3 2019 9.6 2020 10.0 2021 10.3 2022 10.6 Thereafter in the succeeding five years 59.3

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
OPERATING LEASES	OPERATING LEASES The company leases office space in the majority of its locations of business under non-cancelable operating leases. These leases and commitments expire on varying dates through 2025. As of December 31, 2017 , the company's total future commitments by year under non-cancelable operating leases are as follows: $ in millions Total Buildings Other 2018 59.7 57.6 2.1 2019 61.6 59.6 2.0 2020 53.6 51.6 2.0 2021 50.7 49.8 0.9 2022 48.5 48.5 — Thereafter 90.4 90.4 — Gross lease commitments 364.5 357.5 7.0 Less: future minimum payments expected to be received under non-cancelable subleases 6.7 6.7 — Net lease commitments 357.8 350.8 7.0 The company recognized $54.3 million , $46.9 million , and $45.7 million in operating lease expenses in the Consolidated Statements of Income in 2017 , 2016 and 2015 , respectively. These expenses are net of $1.0 million , $10.9 million and $7.6 million of sublease income in 2017 , 2016 and 2015 , respectively.

Other Gains and Losses, Net

Other Gains and Losses, Net	12 Months Ended
	Dec. 31, 2017
OTHER GAINS AND LOSSES, NET
OTHER GAINS AND LOSSES, NET DISCLOSURE [Text Block]	OTHER GAINS AND LOSSES, NET The components of other gains and losses, net, are as follows: $ in millions 2017 2016 2015 Other gains: Gain on sale of investments 11.3 1.5 3.8 Gain on trading investments, net 40.4 14.2 — Foreign exchange hedge gain — 22.0 — Gain on contingent consideration liability 7.6 — 27.1 Net foreign exchange gains 16.2 — — Other realized gains 0.2 1.4 0.9 Total other gains 75.7 39.1 31.8 Other losses: Other-than-temporary impairment of available-for-sale investments (3.2 ) — (2.0 ) Loss on trading investments, net — — (13.5 ) Loss on contingent consideration liability — (7.4 ) — Net foreign exchange losses — (6.0 ) (2.4 ) Foreign exchange hedge loss (21.0 ) — (7.7 ) Realized loss on sale of partnerships — — (7.3 ) Other realized losses — (2.8 ) (0.4 ) Total other losses (24.2 ) (16.2 ) (33.3 ) Other gains and losses, net 51.5 22.9 (1.5 )

Taxation

Taxation	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
TAXATION	TAXATION The company's (provision) for income taxes for the years ended December 31 , 2017 , 2016 and 2015 is summarized as follows: $ in millions 2017 2016 2015 Current: Federal (147.5 ) (161.0 ) (221.0 ) State (30.2 ) (18.9 ) (23.4 ) Foreign (142.2 ) (143.0 ) (161.4 ) (319.9 ) (322.9 ) (405.8 ) Deferred: Federal 63.0 (21.1 ) 11.9 State (11.2 ) (0.9 ) (5.2 ) Foreign (0.1 ) 6.6 1.1 51.7 (15.4 ) 7.8 Total income tax (provision) (268.2 ) (338.3 ) (398.0 ) The net deferred tax recognized in the Consolidated Balance Sheets at December 31 , 2017 and 2016 , respectively, includes the following: $ in millions 2017 2016 Deferred tax assets: Deferred compensation arrangements 57.6 79.1 Accrued rent expenses 7.2 12.3 Tax loss carryforwards 94.6 64.8 Postretirement medical, pension and other benefits 16.6 24.4 Investment basis differences 32.8 58.3 Accrued bonus 8.8 64.8 Other 17.2 24.5 Total deferred tax assets 234.8 328.2 Valuation allowance (94.7 ) (59.0 ) Deferred tax assets, net of valuation allowance 140.1 269.2 Deferred tax liabilities: Deferred sales commissions (11.0 ) (13.5 ) Goodwill and intangibles (377.3 ) (509.6 ) Fixed assets (19.2 ) (27.6 ) Other (8.8 ) (9.2 ) Total deferred tax liabilities (416.3 ) (559.9 ) Net deferred tax assets/(liabilities) (276.2 ) (290.7 ) Deferred income tax assets and liabilities that relate to the same tax jurisdiction are recorded net on the consolidated balance sheet.The deferred tax asset is included in other assets and the deferred tax liability is separately presented on the consolidated balance sheet. The 2017 Tax Act was enacted on December 22, 2017. The 2017 Tax Act significantly revised the U.S. Tax Code by reducing the U.S. federal corporate tax rates and requiring companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred. At December 31, 2017 , the company has not completed the accounting for the tax effects of enacting the 2017 Tax Act; however, the company has made a reasonable estimate of the effects on existing deferred tax balances and the one-time transition tax. The company recognized a provisional income tax benefit of $130.7 million which is included as a component of the provision for income taxes. The company will continue to make and refine all the calculations as additional analysis is completed. In addition, as a more thorough understanding of the tax law is obtained, potential future guidance is issued, and management makes decisions as a result of the 2017 Tax Act, the estimates could potentially be affected. Provisional Amounts Deferred tax assets and liabilities: The company remeasured certain deferred tax assets and liabilities based on the tax rates at which they are expected to reverse in the future, typically 21% under the 2017 Tax Act. However, the company is still analyzing certain aspects of the legislation and refining its calculations. Any updates or changes could affect the measurement of these balances or give rise to new deferred tax amounts. The provisional income tax benefit recorded related to the remeasurement of the deferred tax balance was $130.7 million at December 31, 2017 . Foreign tax effects: The one-time transition tax is based on the total post-1986 earnings and profits (E&P) that were previously deferred from U.S. income taxes. The company does not anticipate incurring an income tax liability and therefore no provision has been made. However, the company has not completed its analysis as to the existence of foreign subsidiaries it may be deemed to indirectly own (or partially own) through attribution or by way of its investment in various fund products which in turn may hold ownership in foreign subsidiaries where the transition tax may apply. Therefore, our determination as to the need for a net transition tax liability may change once this analysis has been completed. At December 31, 2017 the company had tax loss carryforwards accumulated in certain taxing jurisdictions in the aggregate of $413.3 million ( 2016 : $243.8 million ), approximately $35.2 million of which will expire between 2018 and 2020, $15.2 million of which will expire after 2020, with the remaining $362.9 million having an indefinite life. The increase in tax loss carryforwards from 2016 to 2017 of $169.5 million results from the acquisition of the European ETF business ( $160.1 million ) and the impact of foreign exchange translation on non-U.S. dollar denominated losses ( $23.1 million ) with the remainder of the movement due to additional losses not recognized ( $15.8 million ), offset with loss expiration and utilization ( $30.0 million ). A valuation allowance has been recorded against the deferred tax assets related to these losses where a history of losses in the respective tax jurisdiction makes it unlikely that the deferred tax asset will be realized. A reconciliation between the statutory rate and the effective tax rate on income from operations for the years ended December 31 , 2017 , 2016 and 2015 is as follows: 2017 2016 2015 Statutory Rate 35.0 % 35.0 % 35.0 % Foreign jurisdiction statutory income tax rates (9.6 )% (8.1 )% (9.2 )% State taxes, net of federal tax effect 2.2 % 1.6 % 1.6 % Impact of the 2017 Tax Act (9.3 )% — % — % Change in valuation allowance for unrecognized tax losses 0.4 % (0.4 )% (0.1 )% Share Based Compensation (0.3 )% — % — % Other 1.2 % 0.3 % 1.8 % (Gains)/losses attributable to noncontrolling interests (0.8 )% (0.4 )% 0.1 % Effective tax rate per Consolidated Statements of Income 18.8 % 28.0 % 29.2 % The company's subsidiaries operate in several taxing jurisdictions around the world, each with its own statutory income tax rate. As a result, the blended average statutory tax rate will vary from year to year depending on the mix of the profits and losses of the company's subsidiaries. The majority of our profits are earned in the U.S. and the U.K. The enacted U.K. statutory tax rate, for U.S. GAAP purposes, was 19% as of December 31, 2017 . As of December 31, 2017 , the U.S. federal statutory tax rate was 35% . The 2017 Tax Act enacted for U.S. GAAP purposes on December 22, 2017 reduces the U.S. federal statutory tax rate to 21% from January 1, 2018. The division of income/(losses) before taxes between U.S. and foreign for the years ended December 31, 2017 , 2016 and 2015 is as follows: $ in millions (except percentages) 2017 2016 2015 U.S. 638.4 537.5 661.9 CIP - U.S. 0.1 2.4 26.0 Total U.S. income before income taxes 638.5 539.9 687.9 Foreign 754.8 652.0 746.3 CIP - Foreign 35.9 14.7 (72.1 ) Total Foreign income before income taxes 790.7 666.7 674.2 Income from continuing operations before income taxes 1,429.2 1,206.6 1,362.1 As a multinational corporation, the company operates in various locations around the world and we generate substantially all of our earnings from our subsidiaries. Under ASC 740-30 deferred tax liabilities are recognized for taxes that would be payable on the unremitted earnings of the company's subsidiaries, direct investments in CIP and joint ventures, except where it is our intention to continue to indefinitely reinvest the undistributed earnings. Our Canadian and U.S. subsidiaries continue to be directly owned by Invesco Holding Company Limited, a U.K. company, which is directly owned by Invesco Ltd. Our Canadian unremitted earnings, for which we are indefinitely reinvested, are estimated to be $988.0 million at December 31, 2017 , compared with $897.2 million at December 31, 2016 . If distributed as a dividend, Canadian withholding tax of 5.0% would be due. Dividends from our investment in the U.S. should not give rise to additional tax as we are not subject to withholding tax between the U.S. and U.K. Deferred tax liabilities in the amount of $1.4 million ( 2016 : $0.9 million ) for withholding tax on unremitted earnings have been recognized. These subsidiaries have regularly remitted earnings and we expect to continue to remit earnings in the foreseeable future. The U.K. dividend exemption should apply to the remainder of our U.K. subsidiary investments. There is no additional tax on dividends from the U.K. to Bermuda. The company and its subsidiaries file annual income tax returns in the U.S. federal jurisdiction, various U.S. state and local jurisdictions, and in numerous foreign jurisdictions. A number of years may elapse before an uncertain tax position, for which the company has unrecognized tax benefits, is finally resolved. To the extent that the company has favorable tax settlements, or determines that accrued amounts are no longer needed due to a lapse in the applicable statute of limitations or other change in circumstances, such liabilities, as well as the related interest and penalty, would be reversed as a reduction of income tax expense (net of federal tax effects, if applicable) in the period such determination is made. At January 1, 2017 , the company had approximately $10.5 million of gross unrecognized income tax benefits (UTBs), of which $9.5 million represents the amount of unrecognized tax benefits that, if recognized, would favorably affect the effective tax rate in future periods. A reconciliation of the change in the UTB balance from January 1, 2015 , to December 31, 2017 , is as follows: $ in millions Gross Unrecognized Income Tax Benefits Balance at January 1, 2015 6.0 Additions for tax positions related to the current year 2.5 Additions for tax positions related to prior years 2.2 Other reductions for tax positions related to prior years (1.1 ) Reductions for statute closings — Balance at December 31, 2015 9.6 Additions for tax positions related to the current year 0.9 Additions for tax positions related to prior years 0.1 Other reductions for tax positions related to prior years (0.1 ) Reductions for statute closings — Balance at December 31, 2016 10.5 Additions for tax positions related to the current year 0.9 Additions for tax positions related to prior years 11.5 Other reductions for tax positions related to prior years (0.2 ) Reductions for statute closings (3.1 ) Balance at December 31, 2017 19.6 The company recognizes accrued interest and penalties, as appropriate, related to unrecognized tax benefits as a component of the income tax provision. At December 31, 2017 , the total amount of gross unrecognized tax benefits was $19.6 million . 2017 movement is mainly due to a liability of $11.0 million being recorded as a result of an uncertain tax position arising from Illinois Tax Regulation changes enacted in the year and $3.1 million reduction related to the expiration of statute of limitations during the year. Of this total, $16.5 million (net of tax benefits in other jurisdictions and the federal benefit of state taxes) represents the amount of unrecognized tax benefits that, if recognized, would favorably affect the effective tax rate in future periods. The Consolidated Balance Sheet includes accrued interest and penalties of $2.9 million at December 31, 2017 , reflecting $1.2 million for accrued interest and penalties in 2017 (year ended December 31, 2016 : $1.7 million of accrued interest and penalties, $0.5 million of settlement for accrued interest and penalties in 2015; year ended December 31, 2015 : $1.2 million accrued interest and penalties, $0.9 million settlement o f for accrued interests and penalties). As a result of the anticipated legislative changes and potential settlements with taxing authorities, it is reasonably possible that the company's gross unrecognized tax benefits balance may change within the next twelve months by a range of zero to $10.0 million . The company and its subsidiaries are periodically examined by various taxing authorities. With few exceptions, the company is no longer subject to income tax examinations by the primary tax authorities for years prior to 2010. Management monitors changes in tax statutes and regulations and the issuance of judicial decisions to determine the potential impact to uncertain income tax positions. As of December 31, 2017 , management had identified no other potential subsequent events that could have a significant impact on the unrecognized tax benefits balance.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE The calculation of earnings per share is as follows: Years ended December 31, In millions, except per share data 2017 2016 2015 Net income, net of taxes $1,161.0 $868.3 $964.1 Net (income)/loss attributable to noncontrolling interests in consolidated entities (33.7 ) (14.1 ) 4.0 Net income attributable to Invesco Ltd. for basic and diluted EPS calculations 1,127.3 854.2 968.1 Less: Allocation of earnings to restricted shares (33.7 ) (24.8 ) (24.6 ) Net income attributable to common shareholders $1,093.6 $829.4 $943.5 Invesco Ltd: Weighted average shares outstanding - basic 409.4 414.7 428.9 Dilutive effect of non-participating share-based awards 0.5 0.3 0.4 Weighted average shares outstanding - diluted 409.9 415.0 429.3 Common shareholders: Weighted average shares outstanding - basic 409.4 414.7 428.9 Less: Weighted average restricted shares (12.2 ) (12.1 ) (10.9 ) Weighted average common shares outstanding- basic 397.2 402.6 418.0 Dilutive effect of non-participating share-based awards 0.5 0.3 0.4 Weighted average common shares outstanding - diluted 397.7 402.9 418.4 Earnings per share: Basic earnings per share $2.75 $2.06 $2.26 Diluted earnings per share $2.75 $2.06 $2.26 See Note 11 , “Share-Based Compensation,” for a summary of share awards outstanding under the company's share-based payment programs. These programs could result in the issuance of common shares that would affect the measurement of basic and diluted earnings per share. The computation of diluted earnings per share during the years ended December 31 , 2017 , 2016 , and 2015 did not include any anti-dilutive awards. There were 0.1 million contingently issuable shares excluded from the diluted earnings per share computation during the year ended December 31, 2017 ( December 31, 2016 : 0.2 million ; December 31, 2015 : 0.4 million ), because the necessary performance conditions for the shares to be issuable had not yet been satisfied at the end of the respective period.

Geographic Information

Geographic Information	12 Months Ended
	Dec. 31, 2017
Segments, Geographical Areas [Abstract]
GEOGRAPHIC INFORMATION	GEOGRAPHIC INFORMATION The company operates under one business segment, investment management. Geographical information is presented below. There are no revenues or long-lived assets attributed to the company's country of domicile, Bermuda. $ in millions U.S. U.K. Continental Europe/Ireland Canada Asia Total For the year ended December 31, 2017 Revenue from external customers 2,747.9 955.8 999.6 339.0 118.0 5,160.3 Inter-company revenue (5.6 ) 122.8 (243.0 ) (16.9 ) 142.7 — Total operating revenues 2,742.3 1,078.6 756.6 322.1 260.7 5,160.3 Long-lived assets 332.2 118.3 10.0 8.9 21.3 490.7 For the year ended December 31, 2016 Revenue from external customers 2,544.2 930.9 826.8 325.5 107.0 4,734.4 Inter-company revenue (27.0 ) 99.0 (188.9 ) (10.3 ) 127.2 — Total operating revenues 2,517.2 1,029.9 637.9 315.2 234.2 4,734.4 Long-lived assets 331.6 95.9 10.7 9.4 17.1 464.7 For the year ended December 31, 2015 Revenue from external customers 2,622.1 1,153.0 891.9 353.9 102.0 5,122.9 Inter-company revenue (8.6 ) 114.4 (216.7 ) (7.0 ) 117.9 — Total operating revenues 2,613.5 1,267.4 675.2 346.9 219.9 5,122.9 Long-lived assets 306.7 88.3 6.8 10.0 15.1 426.9 Operating revenues reflect the geographical regions from which services are provided.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments and contingencies may arise in the ordinary course of business. The company has transactions with various private equity, real estate and other investment entities sponsored by the company for the investment of client assets in the normal course of business. Certain of the company's investment products are structured as limited partnerships. The company's investment may take the form of the general partner or a limited partner. The entities are structured such that each partner makes capital commitments that are to be drawn down over the life of the partnership as investment opportunities are identified. At December 31, 2017 , the company's undrawn capital and purchase commitments were $292.8 million ( December 31, 2016 : $204.1 million ). The Parent and various company subsidiaries have entered into agreements with financial institutions to guarantee certain obligations of other company subsidiaries. The company would be required to perform under these guarantees in the event of certain defaults. The company has not had prior claims or losses pursuant to these contracts and expects the risk of loss to be remote. As previously announced, the company has entered into an agreement to purchase Guggenheim Investments' ETF business for a purchase price of $1.2 billion , to be paid in cash. It is anticipated that the purchase will be completed within the second quarter of 2018. Legal Contingencies The company is from time to time involved in litigation relating to claims arising in the ordinary course of its business. The nature and progression of litigation can make it difficult to predict the impact a particular lawsuit will have on the company. There are many reasons that the company cannot make these assessments, including, among others, one or more of the following: the proceeding is in its early stages; the damages sought are unspecified, unsupportable, unexplained or uncertain; the claimant is seeking relief other than compensatory damages; the matter presents novel legal claims or other meaningful legal uncertainties; discovery has not started or is not complete; there are significant facts in dispute; and there are other parties who may share in any ultimate liability. In management’s opinion, adequate accrual has been made as of December 31, 2017 to provide for any such losses that may arise from matters for which the company could reasonably estimate an amount. Management is of the opinion that the ultimate resolution of such claims will not materially affect the company’s business, financial position, results of operation or liquidity. Furthermore, in management’s opinion, it is not possible to estimate a range of reasonably possible losses with respect to other litigation contingencies. The investment management industry also is subject to extensive levels of ongoing regulatory oversight and examination. In the United States, United Kingdom, and other jurisdictions in which the company operates, governmental authorities regularly make inquiries, hold investigations and administer market conduct examinations with respect to the company's compliance with applicable laws and regulations. Additional lawsuits or regulatory enforcement actions arising out of these inquiries may in the future be filed against the company and related entities and individuals in the United States, United Kingdom and other jurisdictions in which the company and its affiliates operate. Any material loss of investor and/or client confidence as a result of such inquiries and/or litigation could result in a significant decline in assets under management, which would have an adverse effect on the company’s future financial results and its ability to grow its business. In a separate matter, a Canadian subsidiary of the company had previously received assessments related to prior taxation periods up to and including the year ended December 31, 2012 for goods and services tax that the Canada Revenue Agency (CRA) believes should be levied on certain fees payable. The assessments, including applicable interest, are approximately $7.8 million . The company has secured a letter of credit in the same amount, which has been posted with the CRA as security for payment. The company objected to and appealed the assessments and in May 2017 the Tax Court of Canada ruled in favor of the CRA. The company filed an appeal with the Federal Court of Appeal in June 2017. Management, with advice from tax advisors and counsel, believes it is more likely than not that its position will prevail upon appeal, and accordingly no provision has been recorded in the Consolidated Financial Statements.

Consolidated Investment Product

Consolidated Investment Products	12 Months Ended
	Dec. 31, 2017
Consolidated Investment Products [Abstract]
CONSOLIDATED INVESTMENT PRODUCTS	CONSOLIDATED INVESTMENT PRODUCTS The following table presents the balances related to CIP that are included on the Consolidated Balance Sheets as well as Invesco's net interest in the CIP for each period presented. At December 31, 2017 all CIP are VIEs. As of $ in millions December 31, 2017 December 31, 2016 Cash and cash equivalents of CIP 511.3 742.2 Accounts receivable and other assets of CIP 131.5 106.2 Investments of CIP 5,658.0 5,116.1 Less: Debt of CIP (4,799.8 ) (4,403.1 ) Less: Other liabilities of CIP (498.8 ) (673.4 ) Less: Retained earnings 16.7 19.0 Less: Accumulated other comprehensive income, net of tax (16.6 ) (18.0 ) Less: Equity attributable to redeemable noncontrolling interests (243.2 ) (283.7 ) Less: Equity attributable to nonredeemable noncontrolling interests (258.6 ) (107.2 ) Invesco's net interests in CIP 500.5 498.1 The following table reflects the impact of consolidation of investment products into the Consolidated Statements of Income for the years ended December 31 , 2017 , 2016 and 2015 . Summary of Income Statement Impact of CIP Years ended December 31, $ in millions 2017 2016 2015 Total operating revenues (32.4 ) (22.3 ) (39.2 ) Total operating expenses 10.5 28.7 24.0 Operating income (42.9 ) (51.0 ) (63.2 ) Equity in earnings of unconsolidated affiliates (20.0 ) (8.9 ) (1.7 ) Interest and dividend income — (0.3 ) (4.4 ) Other gains and losses, net (38.4 ) (1.9 ) (3.9 ) Interest and dividend income of CIP 211.6 195.3 253.0 Interest expense of CIP (155.3 ) (123.5 ) (188.9 ) Other gains/(losses) of CIP, net 81.0 7.4 (37.0 ) Income before income taxes 36.0 17.1 (46.1 ) Income tax provision — — — Net income 36.0 17.1 (46.1 ) Net (income)/loss attributable to noncontrolling interests in consolidated entities (33.7 ) (14.1 ) 5.7 Net income attributable to Invesco Ltd. 2.3 3.0 (40.4 ) The company's risk with respect to each investment in CIP is limited to its equity ownership and any uncollected management and performance fees. The company has no right to the benefits from, nor does it bear the risks associated with, these investments, beyond the company's direct investments in, and management and performance fees generated from, the investment products. If the company were to liquidate, these investments would not be available to the general creditors of the company, and as a result, the company does not consider investments held by CIP to be company assets. Additionally, the collateral assets of consolidated collateralized loan obligations (CLOs) are held solely to satisfy the obligations of the CLOs, and the investors in the consolidated CLOs have no recourse to the general credit of the company for the notes issued by the CLOs. CIP are taxed at the investor level and not at the product level; therefore, there is no tax provision reflected in the net impact of CIP. Non-consolidated VIEs At December 31, 2017 , the company's carrying value and maximum risk of loss with respect to VIEs in which the company is not the primary beneficiary was $227.3 million ( December 31, 2016 : $234.4 million ). Balance Sheet information - newly consolidated VIEs/VOEs During the year ended December 31, 2017 , the company invested in and consolidated nineteen new VIEs ( December 31, 2016 : the company invested in and consolidated fifteen new VIEs and one VOE). The tables below illustrate the summary balance sheet amounts related to these products before consolidation into the company. The balances below are reflective of the balances existing at the consolidation date after the initial funding of the investments by the company and unrelated third-party investors. The current period activity for the consolidated funds, including the initial funding and subsequent investment of initial cash balances into underlying investments of CIP, is reflected in the company’s Consolidated Financial Statements. For the year ended December 31, 2017 For the year ended December 31, 2016 $ in millions VIEs VIEs VOEs Cash and cash equivalents of CIP 277.8 609.8 — Accounts receivable and other assets of CIP 11.5 108.5 0.2 Investments of CIP 851.8 1,032.8 49.8 Total assets 1,141.1 1,751.1 50.0 Debt of CIP 544.2 1,013.3 — Other liabilities of CIP 331.5 472.4 — Total liabilities 875.7 1,485.7 — Total equity 265.4 265.4 50.0 Total liabilities and equity 1,141.1 1,751.1 50.0 During the year ended December 31, 2017 , the company determined it was no longer the primary beneficiary of eight VIEs and one VOE. During the year ended December 31, 2016 , the company determined that it was no longer the primary beneficiary of ten VIEs. The amounts deconsolidated from the Consolidated Balance Sheets are illustrated in the table below. There was no net impact to the Consolidated Statements of Income for the years ended December 31, 2017 and December 31, 2016 from the deconsolidation of these investment products. For the year ended December 31, 2017 For the year ended December 31, 2016 $ in millions VIEs VOEs VIEs Cash and cash equivalents of CIP 15.8 — 40.1 Accounts receivable and other assets of CIP 4.1 0.2 19.0 Investments of CIP 358.1 49.8 418.0 Total assets 378.0 50.0 477.1 Debt of CIP 4.2 — — Other liabilities of CIP 3.1 — 23.9 Total liabilities 7.3 — 23.9 Total equity 370.7 50.0 453.2 Total liabilities and equity 378.0 50.0 477.1 The following tables present the fair value hierarchy levels of certain CIP balances which are measured at fair value as of December 31, 2017 and December 31, 2016 : As of December 31, 2017 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV as a practical expedient Assets: Bank loans 4,894.2 — 4,894.2 — — Bonds 302.0 — 302.0 — — Equity securities 203.2 198.8 4.4 — — Equity and fixed income mutual funds 19.0 19.0 — — — Investments in other private equity funds 163.4 — — — 163.4 Real estate investments 76.2 — — 76.2 — Total assets at fair value 5,658.0 217.8 5,200.6 76.2 163.4 As of December 31, 2016 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV as a Practical expedient Assets: Bank loans 4,397.8 — 4,397.8 — — Bonds 370.9 — 370.9 — — Equity securities 167.4 166.0 1.4 — — Equity and fixed income mutual funds 13.0 13.0 — — — Investments in other private equity funds 68.6 — — — 68.6 Real estate investments 40.7 — — 40.7 — Investments in fixed income fund of funds 57.7 — — — 57.7 Total assets at fair value 5,116.1 179.0 4,770.1 40.7 126.3 The following table shows a reconciliation of the beginning and ending fair value measurements for level 3 assets and liabilities using significant unobservable inputs: Year ended December 31, 2017 Year ended December 31, 2016 $ in millions Level 3 Assets Level 3 Assets Beginning balance 40.7 388.6 Adjustment for adoption of ASU 2015-02 — (388.6 ) Purchases 15.1 39.4 Sales (4.5 ) — Gains and losses included in the Consolidated Statements of Income* 24.9 1.3 Ending balance 76.2 40.7 ____________ * Included in gains/(losses) of CIP, net in the Consolidated Statement of Income for the year ended December 31, 2017 are $24.5 million in net unrealized gains attributable to investments still held at December 31, 2017 by CIP (year ended December 31, 2016 : $1.3 million net unrealized gains attributable to investments still held at December 31, 2016 ). Unforeseen events might occur that would subsequently change the fair values of the investments (and therefore the debt of CLOs, since it is measured as a calculated value based upon the fair value of the assets of CLOs, but the impact of such changes would be limited to the change in the fair values of the company's investments in these products. The impact of any gains or losses resulting from valuation changes in the investments of non-CLO CIP attributable to the interests of third parties are offset by resulting changes in gains and losses attributable to noncontrolling interests in consolidated entities and therefore do not have a material effect on the financial condition, operating results (including earnings per share), liquidity or capital resources of the company's common shareholders. Similarly, any gains or losses resulting from valuation changes in the investments of CLOs attributable to the interests of third parties are offset by the calculated value of the notes issued by the CLOs (offsetting in other gains/(losses) of CIP) and therefore also do not have a material effect on the financial condition, operating results (including earnings per share), liquidity or capital resources of the company's common shareholders. Value of consolidated CLOs The company elected the fair value option for collateral assets held and notes issued by its consolidated CLOs to eliminate the measurement and recognition inconsistency that would otherwise arise from measuring assets and liabilities and recognizing the related gains and losses on different accounting bases. On January 1, 2015 the company adopted ASU 2014-13 and has elected the measurement alternative for the consolidated CLOs under which the notes issued by the CLOs are measured based on the fair value of the assets of the CLOs. The collateral assets held by consolidated CLOs are primarily invested in senior secured bank loans, bonds, and equity securities. Bank loan investments at December 31, 2017 of $4,859.3 million ( December 31, 2016 : $4,397.8 million ), which comprise the majority of consolidated CLO portfolio collateral, are senior secured corporate loans from a variety of industries, including but not limited to the aerospace and defense, broadcasting, technology, utilities, household products, healthcare, oil and gas, transportation, real estate, packaging, and finance industries. Bank loan investments mature at various dates between 2018 and 2026 , pay interest at Libor plus a spread of up to 10.0% , and typically range in S&P credit rating categories from BBB down to unrated. Interest income on bank loans and bonds is recognized based on the unpaid principal balance and stated interest rate of these investments on an accrual basis. At December 31, 2017 , the unpaid principal balance exceeds the fair value of the senior secured bank loans and bonds by approximately $84.6 million ( December 31, 2016 : the unpaid principal balance exceeded the fair value of the senior secured bank loans and bonds by approximately $96.6 million ). Approximately 0.41% of the collateral assets are in default as of December 31, 2017 ( December 31, 2016 : approximately 0.3% of the collateral assets were in default). CLO investments are valued based on price quotations provided by third party pricing sources. These third party sources aggregate indicative price quotations daily to provide the company with a price for the CLO investments. The company has developed internal controls to review the reasonableness and completeness of these price quotations on a daily basis. If necessary, price quotations are challenged through the third-party pricing source price challenge process. In addition, the company's internal valuation committee conducts an annual due diligence review of all independent third-party pricing sources to review the provider's valuation methodology as well as ensure internal controls exist over the valuation of the CLO investments. In the event that the third-party pricing source is unable to price an investment, other relevant factors, data and information are considered, including: i) information relating to the market for the investment, including price quotations for and trading in the investment and interests in similar investments, the market environment, and investor attitudes towards the investment and interests in similar investments; ii) the characteristics of and fundamental analytical data relating to the investment, including, for senior secured corporate loans, the cost, size, current interest rate, period until next interest rate reset, maturity and base lending rate, the terms and conditions of the senior secured corporate loan and any related agreements, and the position of the senior secured corporate loan in the borrower's debt structure; iii) the nature, adequacy and value of the senior secured corporate loan's collateral, including the CLO's rights, remedies and interests with respect to the collateral; iv) for senior secured corporate loans, the creditworthiness of the borrower, based on an evaluation of its financial condition, financial statements and information about the business, cash flows, capital structure and future prospects; v) the reputation and financial condition of the agent and any intermediate participants in the senior secured corporate loan; and vi) general economic and market conditions affecting the fair value of the senior secured corporate loan. Notes issued by consolidated CLOs mature at various dates between 2025 and 2031 and have a weighted average maturity of 10.0 years. The notes are issued in various tranches with different risk profiles. The interest rates are generally variable rates based on Libor plus a pre-defined spread, which varies from 0.92% for the more senior tranches to 8.25% for the more subordinated tranches. The investors in this debt are not affiliated with the company and have no recourse to the general credit of the company for this debt. Fair value of consolidated real estate funds The real estate investment vehicles use one or more valuation techniques (e.g. the market approach, the income approach, or the recent transaction "cost" approach) for which sufficient and reliable data is available to value investments classified within level 3. The use of the market approach generally consists of using comparable market transactions, while the use of the income approach generally consists of the net present value of estimated future cash flows, adjusted as appropriate for liquidity, credit, market and/or other risk factors. The inputs used by the real estate funds in estimating the value of level 3 investments include the original transaction price, recent transactions in the same or similar instruments, as well as completed or pending third-party transactions in the underlying investment or comparable investments. Level 3 investments may also be adjusted to reflect illiquidity and/or non-transferability. Other inputs used include discount rates, cap rates, and income and expense assumptions. The fair value measurement of level 3 investments does not include transaction costs and acquisition fees that may be capitalized as part of the investment's cost basis. Fair value of consolidated partnership entities Consolidated private equity funds are generally structured as partnerships. Generally, the investment strategy of underlying holdings in these partnerships is to seek capital appreciation through direct investments in public or private companies with compelling business models or ideas or through investments in partnership investments that also invest in similar private or public companies. Various strategies may be used. Companies targeted could be distressed organizations, targets of leveraged buyouts or fledgling companies in need of venture capital. Investors in CIP generally may not redeem their investment until the partnership liquidates. Generally, the partnerships have a life that ranges from seven to twelve years unless dissolved earlier. The general partner may extend the partnership term up to a specified period of time as stated in the Partnership Agreement. Some partnerships allow the limited partners to cause an earlier termination upon the occurrence of certain events as specified in the Partnership Agreement. For private equity partnerships, fair value is determined by reviewing each investment for the sale of additional securities of an issuer to sophisticated investors or for investee financial conditions and fundamentals. Publicly traded portfolio investments are carried at market value as determined by their most recent quoted sale, or if there is no recent sale, at their most recent bid price. For these investments held by CIP, level 1 classification indicates that fair values have been determined using unadjusted quoted prices in active markets for identical assets that the partnership has the ability to access. Level 2 classification may indicate that fair values have been determined using quoted prices in active markets but give effect to certain lock-up restrictions surrounding the holding period of the underlying investments. The fair value of level 3 investments held by CIP are derived from inputs that are unobservable and which reflect the limited partnerships' own determinations about the assumptions that market participants would use in pricing the investments, including assumptions about risk. These inputs are developed based on the partnership's own data, which is adjusted if information indicates that market participants would use different assumptions. The partnerships which invest directly into private equity portfolio companies (direct private equity funds) take into account various market conditions, subsequent rounds of financing, liquidity, financial condition, purchase multiples paid in other comparable third-party transactions, the price of securities of other companies comparable to the portfolio company, and operating results and other financial data of the portfolio company, as applicable. The partnerships which invest into other private equity funds (funds-of-funds) take into account information received from those underlying funds, including their reported net asset values and evidence as to their fair value approach, including consistency of their fair value application. These investments do not trade in active markets and represent illiquid long-term investments that generally require future capital commitments. The partnerships' reported share of the underlying net asset values of the underlying funds is used as a practical expedient, as allowed by ASC Topic 820, in arriving at fair value. Quantitative Information about Level 3 Fair Value Measurements The following table shows significant unobservable inputs used in the fair value measurement of level 3 assets at December 31, 2017 : Assets and Liabilities * Fair Value at December 31, 2017 ($ in millions) Valuation Technique Unobservable Inputs Range Weighted Average (by fair value) Real Estate Investments $76.2 Discounted Cash Flow Discount rate 7% - 33% 17.0 % Terminal capitalization rate 5.3% 5.3 % Average rent growth rate 2%-3% 2.5 % At December 31, 2016 , $40.7 million of investments held by consolidated real estate funds were valued using recent private market transactions. The following narrative will indicate the sensitivity of inputs illustrating the impact of significant increases to the inputs. A directionally opposite impact would apply for significant decreases in these inputs: • For real estate investments, a change in the average rent growth rate would result in a directionally-opposite change in the assumptions for discount rate and terminal capitalization rate. Significant increases in the average growth rate would result in significantly higher fair values. Significant increases in the assumptions for discount rate and terminal capitalization rate in isolation would result in significantly lower fair value measurements. The table below summarizes as of December 31, 2017 and December 31, 2016 , the nature of investments that are valued using the NAV as a practical expedient and any related liquidation restrictions or other factors which may impact the ultimate value realized: December 31, 2017 December 31, 2016 in millions, except term data Fair Value Total Unfunded Commitments Weighted Average Remaining Term (2) Fair Value Total Unfunded Commitments Weighted Average Remaining Term (2) Private equity funds (1) $163.4 $53.9 5.5 years $68.6 $41.9 7.0 years Investments in fixed income fund of funds (3) — — n/a 57.7 — n/a ____________ (1) These investments are not subject to redemption; however, for certain funds, the investors may sell or transfer their interest, which may require approval by the general partner of the underlying funds. (2) These investments are expected to be returned through distributions as a result of liquidations of the funds' underlying assets over the weighted average periods indicated. (3) Investment may be redeemed on a monthly basis. For investments held by consolidated private equity funds, significant increases in discounts in isolation would result in significantly lower fair value measurements, while significant increases in revenue multiple assumptions in isolation would result in significantly higher fair value measurements. An increase in discount assumptions would result in a directionally opposite change in the assumptions for revenue multiple resulting in lower fair value measurements. Fair Value of Equity Securities, Bonds, and Equity/Fixed Income Mutual Funds Equity securities are valued under the market approach through use of quoted prices on an exchange. To the extent these securities are actively traded, valuation adjustments are not applied and they are categorized within level 1 of the valuation hierarchy; otherwise, they are categorized in level 2 or level 3 depending on the inputs used. Bonds are fair valued using an evaluated quote provided by an independent pricing service. Evaluated quotes provided by the pricing service may be determined without exclusive reliance on quoted prices, and may reflect appropriate factors such as institution-size trading in similar groups of securities, developments related to specific securities, yield, quality, type of issue, coupon rate, maturity, individual trading characteristics and other market data. Depending on the nature of the inputs, these investments are categorized as level 1, 2, or 3. Equity and fixed income mutual funds are valued under the market approach through the use of quoted market prices available in an active market and is classified within level 1 of the valuation hierarchy; there is no modeling or additional information needed to arrive at the fair values of these investments.

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
RELATED PARTIES	RELATED PARTIES Certain managed funds are deemed to be affiliated entities under the related party definition in ASC 850, "Related Party Disclosures." Additionally, related parties include those defined in the company's proxy statement. Affiliated balances are illustrated in the tables below: Years ended December 31, $ in millions 2017 2016 2015 Affiliated operating revenues: Investment management fees 3,624.7 3,274.3 3,565.8 Service and distribution fees 851.2 822.3 854.0 Performance fees 73.8 21.5 29.2 Other 59.1 79.8 108.5 Total affiliated operating revenues 4,608.8 4,197.9 4,557.5 As of December 31, $ in millions 2017 2016 Affiliated asset balances: Cash and cash equivalents 875.5 476.2 Unsettled fund receivables 204.0 253.2 Accounts receivable 359.9 344.4 Investments 608.5 728.3 Assets held for policyholders 12,444.2 8,224.2 Other assets 9.2 2.9 Total affiliated asset balances 14,501.3 10,029.2 Affiliated liability balances: Accrued compensation and benefits 90.7 76.5 Accounts payable and accrued expenses 64.5 94.7 Unsettled fund payables 288.8 318.7 Total affiliated liability balances 444.0 489.9

Business optimization

Business optimization	12 Months Ended
	Dec. 31, 2017
Restructuring Charges [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	BUSINESS OPTIMIZATION Business optimization charges of $58.0 million were recorded in 2017 ( 2016 : $49.9 million ; 2015 : $16.2 million ), including $30.0 million of staff severance costs recorded in employee compensation, $25.3 million recorded in general and administrative expenses, and $2.7 million recorded in property, office and technology expenses associated with a business transformation initiative. This is a continuation of efforts to transform several key business support functions to become more effective and efficient by leveraging shared service centers, outsourcing, automation of key processes and optimization of the company's office footprint. Incremental implementation costs in 2018 are estimated to be up to $35.0 million . The Consolidated Balance Sheet at December 31, 2017 does not include any material liabilities related to business optimization efforts.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	On January 31, 2018 , the company declared a fourth quarter 2017 dividend of 29.0 cents per share, payable on March 2, 2018 , to shareholders of record at the close of business on February 15, 2018 with an ex-dividend date of February 14, 2018 .

Accounting Policies (Policy)

Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Corporate Information	Corporate Information Invesco Ltd. (Parent) and all of its consolidated entities (collectively, the company or Invesco) provide retail and institutional clients with an array of global investment management capabilities. The company operates globally and its sole business is investment management.
Basis of Accounting and Consolidation	Basis of Accounting and Consolidation The Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States and with rules and regulations of the Securities and Exchange Commission and consolidate the financial statements of the Parent and all of its controlled subsidiaries. In the opinion of management, the Consolidated Financial Statements reflect all adjustments, consisting of normal recurring accruals, which are necessary for the fair presentation of the financial condition and results of operations for the periods presented. All significant intercompany transactions, balances, revenues and expenses are eliminated upon consolidation. The company provides investment management services to, and has transactions with, various retail mutual funds and similar entities, private equity funds, real estate funds, fund-of-funds, collateralized loan obligations (CLOs), and other investment products sponsored by the company in the normal course of business for the investment of client assets. The company serves as the investment manager, making day-to-day investment decisions concerning the assets of these products. In addition to consolidating the financial statements of the Parent and all of its controlled subsidiaries, the Consolidated Financial Statements include the consolidation of certain investment products (Consolidated Investment Products or CIP) that meet the definition of either a voting rights entity (VOE), if the company is deemed to have a controlling financial interest in the fund, or a variable interest entity (VIE), if the company has been deemed to be the primary beneficiary of the fund. Certain of these investment products, typically CLOs, funds that are structured as partnership entities (such as private equity funds, real estate funds, and fund-of-funds), and certain non-U.S. mutual funds, are considered, for accounting and consolidation analysis purposes, to be VIEs if the VIE criteria are met. A VIE, in the context of the company and its managed funds, is a fund that does not have sufficient equity to finance its operations without additional subordinated financial support, or a fund for which the risks and rewards of ownership are not directly linked to voting interests. If the company is deemed to have the power to direct the activities of the fund that most significantly impact the fund's economic performance, and the obligation to absorb losses/right to receive benefits from the fund that could potentially be significant to the fund, then the company is deemed to be the fund's primary beneficiary and is required to consolidate the fund. The company's economic risk with respect to each investment in a CIP is limited to its equity ownership and any uncollected management and performance fees. See Note 19 , "Consolidated Investment Products," for additional information regarding the impact of CIP. Consolidation Analysis The company inventories its funds by vehicle type on a quarterly basis. The company assesses modifications to existing funds on an ongoing basis to determine if a significant reconsideration event has occurred. The consolidation analysis includes a detailed review of the terms of the fund's governing documents and a comparison of the significant terms against the consolidation criteria in ASC Topic 810, including a determination of whether the fund is a VIE or a VOE. Seed money and co-investments in managed funds in which the company has determined that it is the primary beneficiary or in which the company has a controlling financial interest are consolidated if the impact of doing so is deemed material. Otherwise, these investments are accounted for as described in the “Investments” accounting policy below. Upon consolidation of an investment product, the company's gain or loss on its investment (before consolidation) eliminates with the company's share of the offsetting loss or gain in the fund. Upon consolidation of CLOs, the company's and the funds' accounting policies are effectively aligned, resulting in the reclassification of the company's gain or loss (representing the changes in the market value of the company's holding in the consolidated fund) from other comprehensive income into other gains/losses. The net impact from consolidation of funds previously carried as available-for-sale investments to net income attributable to Invesco Ltd. in each period primarily represents the changes in the value of the company's holdings in its consolidated CLOs. Consolidation of CLOs A significant portion of VIEs are CLOs. CLOs are investment vehicles created for the sole purpose of issuing collateralized loan instruments that offer investors the opportunity for returns that vary with the risk level of their investment. The notes issued by the CLOs are backed by diversified collateral asset portfolios consisting primarily of loans or structured debt. For managing the collateral of the CLO entities, the company earns investment management fees, including in some cases subordinated management fees, as well as contingent performance fees. The company has invested in certain of the entities, generally taking a portion of the unrated, junior subordinated position. The company's investments in CLOs are generally subordinated to other interests in the entities and entitle the company and other subordinated tranche investors to receive the residual cash flows, if any, from the entities. The company's subordinated interest can take the form of (1) subordinated notes, (2) income notes or (3) preference/preferred shares. The company has determined that, although the junior tranches have certain characteristics of equity, they should be accounted for and disclosed as debt on the company's Consolidated Balance Sheets, as the subordinated and income notes have a stated maturity indicating a date for which they are mandatorily redeemable. The preference shares are also classified as debt, as redemption is required only upon liquidation or termination of the CLO and not of the company. The company determined that it was the primary beneficiary of certain CLOs, as it has the power to direct the activities of the CLOs that most significantly impact the CLOs' economic performance, and the obligation to absorb losses/right to receive benefits from the CLOs that could potentially be significant to the CLOs. The primary beneficiary assessment includes an analysis of the rights of the company in its capacity as investment manager. In some CLOs, the company's role as investment manager provides that the company contractually has the power, as defined in ASC Topic 810, to direct the activities of the CLOs that most significantly impact the CLOs' economic performance, such as managing the collateral portfolio and the CLOs' credit risk. In other CLOs, the company determined that it does not have this power in its role as investment manager due to certain rights held by other investors in the products or restrictions that limit the company's ability to manage the collateral portfolio and its credit risk. Additionally, the primary beneficiary assessment includes an analysis of the company's rights to receive benefits and obligations to absorb losses associated with its first loss position and management/performance fees. The company has elected the fair value option under ASC Topic 825-10-25 to measure the assets of all consolidated CLOs at fair value. All of the investments held by VIEs are presented at fair value in the company's Consolidated Balance Sheets at December 31, 2017 and 2016 . The company adopted Accounting Standards Update 2014-13, "Measuring the Financial Assets and the Financial Liabilities of a Consolidated Collateralized Financing Entity" (ASU 2014-13) on January 1, 2015, and accordingly the notes issued by consolidated CLOs are no longer carried at fair value but are now measured under the measurement alternative discussed in ASU 2014-13. The measurement alternative requires that the reporting entity measure both the financial assets and the fair value of the financial liabilities of the CFE by using the more observable of the fair value of the financial assets and the fair value of the financial liabilities, removing any measurement difference previously recorded as net income (loss) attributable to noncontrolling interests in consolidated entities and as an adjustment to retained earnings appropriated for investors in CIP. The company’s subsequent earnings from consolidated CLOs reflect changes in fair value of its own economic interests in the CLOs. Gains or losses on assets and liabilities of the CLOs are not attributed to noncontrolling interests but are offset in other gains/(losses) of CIP. Consolidation of Private Equity, Real Estate, and Fund-of-Funds The company also consolidates certain private equity funds and from time to time real estate funds that are structured as partnerships in which the company is the general partner receiving a management and/or performance fee. Private equity investments made by the underlying funds consist of direct investments in, or fund investments in other private equity funds that hold direct investments in, equity or debt securities of operating companies that are generally not initially publicly traded. Private equity funds are considered investment companies and are therefore accounted for under ASC Topic 946, “Financial Services - Investment Companies.” The company has retained the specialized industry accounting principles of these investment products in its Consolidated Financial Statements. See Note 19 , “Consolidated Investment Products,” for additional details. Consolidation basis The Consolidated Financial Statements have been prepared primarily on the historical cost basis; however, certain items are presented using other bases such as fair value, where such treatment is required or voluntarily elected, as discussed above. The financial statements of subsidiaries, with the exception of certain CIP, are prepared for the same reporting period as the Parent and use consistent accounting policies, which, where applicable, have been adjusted to U.S. GAAP from local generally accepted accounting principles or reporting regulations. The financial information of certain CIP is included in the company's Consolidated Financial Statements on a one -month or a three -month lag based upon the availability of fund financial information. Noncontrolling interests in consolidated entities represents the interests in certain entities consolidated by the company either because the company has control over the entity or has determined that it is the primary beneficiary, but of which the company does not own all of the entity's equity. To the extent that noncontrolling interests represent equity which is redeemable or convertible for cash or other assets at the option of the equity holder, these are deemed to represent temporary equity, and are classified as equity attributable to redeemable noncontrolling interests in the Consolidated Balance Sheets. Nonredeemable noncontrolling interests are classified as a component of permanent equity.
Use of Estimates	Use of Estimates In preparing the Consolidated Financial Statements, management is required to make estimates and assumptions that affect reported revenues, expenses, assets, liabilities, and disclosure of contingent liabilities. The primary estimates and assumptions made relate to goodwill and intangible impairment, certain investments which are carried at fair value, post-employment benefit plan obligations, and taxes. Additionally, estimation is involved when determining investment and debt valuation for certain CIP; however, changes in the fair values of these amounts are largely offset by noncontrolling interests. Use of available information and application of judgment are inherent in the formation of estimates. Actual results in the future could differ from such estimates and the differences may be material to the Consolidated Financial Statements.
Reclassifications	Reclassifications The presentation of certain prior period amounts has been reclassified to be consistent with the current period presentation. Such reclassifications had no impact on total operating revenues, operating expenses, net income, total assets, total liabilities, or equity attributable to Invesco Ltd.
Acquisition Accounting	Acquisition Accounting In accordance with ASC Topic 805, “Business Combinations," any excess of the cost of the acquisition over the fair values of the identifiable net assets acquired attributable to the company is recognized as goodwill. With certain exceptions, 100% of the fair values of assets acquired, liabilities assumed, and noncontrolling interests is recognized in acquisitions of less than a 100% controlling interest when the acquisition constitutes a change in control of the acquired entity. Additionally, when partial ownership in an acquiree is obtained and it is determined that the company controls the acquiree, the assets acquired, liabilities assumed and any noncontrolling interests are recognized and consolidated at 100% of their fair values at that date, regardless of the percentage ownership in the acquiree. As goodwill is calculated as a residual, all goodwill of the acquired business, not just the company's share, is recognized under this “full-goodwill” approach. Noncontrolling interests are stated at the noncontrolling shareholder's proportion of the pre-acquisition carrying values of the acquired net assets. The results of entities acquired or sold during the year are included from or to the date control changes. Contingent consideration obligations that are elements of consideration transferred are recognized as of the acquisition date as part of the fair value transferred in exchange for the acquired business. Acquisition-related costs incurred in connection with a business combination are expensed.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash held at banks and short-term investments with a maturity upon acquisition of three months or less. Cash and cash equivalents of CIP are not available for general use by the company. Cash balances may not be readily accessible to the Parent due to capital adequacy requirements of certain of our subsidiaries. These and other similar provisions of applicable laws and regulations may have the effect of limiting withdrawals of capital, repayment of intercompany loans and payment of dividends by such entities. All of our regulated EU subsidiaries are subject to consolidated capital requirements under EU Directives, including those arising from the EU's Capital Requirements Directive and the U.K.'s Internal Capital Adequacy Assessment Process (ICAAP), and capital is maintained within this sub-group to satisfy these regulations. We meet these requirements in part by holding cash and cash equivalents. This retained cash can be used for general business purposes in the European sub-group in the countries where it is located. Due to the capital restrictions, the ability to transfer cash between certain jurisdictions may be limited. In addition, transfers of cash between international jurisdictions may have adverse tax consequences. The company is in compliance with all regulatory minimum net capital requirements. In addition, the company is required to hold cash deposits with clearing organizations or to otherwise segregate cash to maintain compliance with federal and other regulations in connection with its UIT broker dealer entity. At December 31, 2017 these cash deposits totaled $11.4 million (year ended December 31, 2016 : $11.4 million ).
Unsettled Fund Receivables and Payables	Unsettled Fund Receivables and Payables The company records unsettled fund receivables from underlying fund investors in certain fund products outside the U.S. when these investors place unsettled investments into the funds. Additionally, the company records unsettled fund receivables from certain non-U.S. funds during the settlement period when underlying fund investors redeem their holdings. Settlement periods for both receivables from underlying investors and funds are generally less than four days. Additionally, in its capacity as sponsor of UITs, the company records receivables from brokers, dealers, and clearing organizations for unsettled sell trades of securities and UITs in addition to receivables from customers for unsettled sell trades of UITs. The company also records payables to brokers, dealers, and clearing organization for unsettled buy trades of securities and UITs in addition to payables to customers for unsettled buy trades of securities and UITs. The presentation of the unsettled fund receivables and substantially offsetting payables at trade date reflects the legal relationship between the underlying investor and the company.
Accounts Receivable and Payable	Accounts Receivable and Payable Accounts receivable and payable are recorded at their original invoice amounts. Accounts receivable are also recorded less any allowance for uncollectible amounts.
Investments	Investments The majority of the company’s investment balances relate to balances held in affiliated funds. In the normal course of business, the company invests in various types of affiliated investment products, either as “seed money” or as longer-term investments alongside third-party investors, typically referred to as “co-investments.” Seed money investments are investments held in Invesco managed funds with the purpose of providing capital to the funds during their development periods to allow the funds to achieve critical mass, establish their track records, and obtain third-party investments. Seed money may also be held for regulatory purposes in certain jurisdictions. Co-investments are often required of the investment manager by third-party investors in closed-ended funds to demonstrate an aligning of the investment manager’s interests with those of the third-party investors. The company also invests in affiliated funds in connection with its deferred compensation plans, whereby certain employees defer portions of their annual bonus into funds. Investments are categorized in this Report as available-for-sale, trading, equity method, foreign time deposits, and other investments. See Note 3 “Investments” for additional details. Available-for-sale investments include seed money, co-investments in affiliated CLOs, and investments in other debt securities. Available-for-sale investments are measured at fair value. Gains or losses arising from changes in the fair value of available-for-sale investments are recognized in accumulated other comprehensive income, net of tax, until the investment is sold or otherwise disposed of, or if the investment is determined to be other-than-temporarily impaired, at which time the cumulative gain or loss previously reported in equity is included in income. The specific identification method is used to determine the realized gain or loss on securities sold or otherwise disposed. Trading investments include investments held to settle the company’s deferred compensation plan liabilities, seed money, as well as trading and investing activities in equity and debt securities entered into in its capacity as sponsor of UITs, and other equity securities. Trading securities are securities bought and held principally for the purpose of selling them in the near term. Trading investments are measured at fair value. Gains or losses arising from changes in the fair value of trading investments are included in income. Equity method investments include investments over which the company is deemed to have significant influence, including corporate joint ventures and non-controlled entities in which the company's ownership is between 20 and 50 percent, and co-investments in certain managed funds generally structured as partnerships or similar vehicles. Investments in joint ventures are investments jointly controlled by the company and external parties. Co-investments in managed funds structured as partnerships or similar vehicles include private equity, real estate, and fund-of-funds. The equity method of accounting requires that the investment is initially recorded at cost, including any excess value paid over the book value of the investment acquired. The carrying amount of the investment is increased or decreased to recognize the company's share of the after-tax profit or loss of the investee after the date of acquisition. The proportionate share of income or loss is included in equity in earnings of unconsolidated affiliates in the Consolidated Statements of Income, and the proportionate share of other comprehensive income or loss is included in accumulated other comprehensive income in the Consolidated Balance Sheets. Seed money and co-investments in managed funds are required to be consolidated by the company if certain criteria are met. Upon consolidation of material balances, the company’s seed money or co-investment balance is eliminated, and the underlying investments of the managed fund are reflected on the company’s Consolidated Balance Sheets at fair value. These underlying investments are presented in the company's Consolidated Financial Statements as CIP investments. See “Basis of Accounting and Consolidation” for additional information regarding the consolidation criteria. If the company subsequently determines that it no longer controls the managed funds in which it has invested, the company will deconsolidate the funds. Any remaining holding in the managed funds is then accounted for on the bases described above. Fair value is determined using a valuation hierarchy (discussed in Note 2 , “Fair Value of Assets and Liabilities”), generally by reference to an active trading market, using quoted closing or bid prices as of each reporting period end. When a readily ascertainable market value does not exist for an investment, the fair value is calculated based on the expected cash flows of its underlying net asset base, taking into account applicable discount rates and other factors. Judgment is used to ascertain if a formerly active market has become inactive and in determining fair values when markets have become inactive. The company evaluates the carrying value of investments for impairment on a quarterly basis. In its impairment analysis, the company takes into consideration numerous criteria, including the duration and extent of any decline in fair value, the intent and ability of the company to hold the security for a period of time sufficient for a recovery in value, recent events specific to the issuer or industry and external credit ratings and recent downgrades with respect to issuers of debt securities held. If the decline in value is determined to be other-than-temporary, the carrying value of the security is generally written down to fair value through the income statement. If the fair value of a debt security, however, is less than its amortized cost, the decline in value is determined to be other-than-temporary, and the company intends to sell the debt security or it is more likely than not that the company will be required to sell the debt security before the recovery of its amortized cost basis, the entire difference between the investment's amortized cost basis and its fair value is recognized as an other-than-temporary impairment through the income statement. If the company does not intend to sell the debt security, and it is not more likely than not that the company will be required to sell the debt security before recovery of its amortized cost basis, then the other-than-temporary impairment is separated into two components: a) the amount representing the credit loss, which is recorded as a charge in the Consolidated Statements of Income, and b) the amount related to all other factors, which is recognized in the Consolidated Statements of Comprehensive Income, net of tax.
Assets Held for Policyholders and Policyholder Payables	Assets Held for Policyholders and Policyholder Payables One of the company's subsidiaries, Invesco Perpetual Life Limited, is an insurance entity that was established to facilitate retirement savings plans in the U.K. The entity holds assets that are managed for its clients on its balance sheet with an equal and offsetting liability to the policyholders, which is linked to the value of the investments. The investments are legally segregated and are generally not subject to claims that arise from any of the company's other businesses. Investments and policyholder payables held by this business meet the definition of financial instruments and are carried in the Consolidated Balance Sheets as separate account assets and liabilities at fair value in accordance with ASC Topic 944, “Financial Services - Insurance.” Changes in fair value are recorded and offset to zero in the Consolidated Statements of Income in other operating revenues. Management fees earned from policyholder investments are accounted for as described in the company's revenue recognition accounting policy.
Deferred Sales Commissions	Deferred Sales Commissions Mutual fund shares sold without a sales commission at the time of purchase typically have an asset-based fee (12b-1 fee) that is charged to the fund over a period of years and a contingent deferred sales charge (CDSC). The CDSC is an asset-based fee that is charged to investors that redeem during a stated period. Commissions paid at the date of sale to brokers and dealers for sales of mutual funds that have a CDSC are capitalized and amortized over a period not to exceed the redemption period of the related fund (generally up to six years ). The deferred sales commission asset, which is included in prepaid assets in our Consolidated Balance Sheets, is reviewed periodically for impairment by reviewing the recoverability of the asset based on estimated future fees to be collected.
Property, Equipment, Software and Depreciation	Property, Equipment, Software and Depreciation Property, equipment and software includes owned property, leasehold improvements, computer hardware/software and other equipment and is stated at cost less accumulated depreciation or amortization and any previously recorded impairment in value. Expenditures for major additions and improvements are capitalized; minor replacements, maintenance and repairs are charged to expense as incurred. Amounts incurred are presented as work-in-progress until the construction or purchase of the property and equipment is substantially complete and ready for its intended use, which, at that point, will begin to be depreciated or amortized. Depreciation is provided on property and equipment at rates calculated to write off the cost, less estimated residual value, of each asset on a straight-line basis over its expected useful life: owned buildings over 50 years , leasehold improvements over the shorter of the lease term or useful life of the improvement; and computers and other various equipment between three and seven years. Purchased and internally developed software is capitalized where the related costs can be measured reliably, and it is probable that the asset will generate future economic benefits, and amortized into operating expenses on a straight-line basis over its useful life, generally over five to seven years. The company capitalizes qualified internal and external costs incurred during the application development stage for internally developed software in accordance with ASC Topic 350-40, “Intangibles - Goodwill and Other - Internal-Use Software.” The company reevaluates the useful life determination for property and equipment each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life. On sale or retirement, the asset cost and related accumulated depreciation are removed from the Consolidated Financial Statements and any related gain or loss is reflected in income. The carrying amounts of property and equipment are reviewed for impairment when events or changes in circumstances indicate that the carrying values may not be recoverable. At each reporting date, an assessment is made for any indication of impairment. If an indication of impairment exists, recoverability is tested by comparing the carrying amount of the asset to the net undiscounted cash flows expected to be generated from the asset. If those net undiscounted cash flows do not exceed the carrying amount (i.e. the asset is not recoverable), the next step would be performed, which is to determine the fair value of the asset and record an impairment charge, if any.
Intangible Assets	Intangible Assets Intangible assets identified on the acquisition of a business are capitalized separately from goodwill if the fair value can be measured reliably on initial recognition (transaction date) and, if they are determined to be finite-lived, are amortized and recorded as operating expenses on a straight-line basis over their useful lives, from two to twelve years, which reflects the pattern in which the economic benefits are realized. Intangible assets consist primarily of mutual fund and other client management contracts, customer relationships and distribution agreements. The company considers its own assumptions, which require management's judgment, about renewal or extension of the term of the arrangement, consistent with its expected use of the asset. A change in the useful life of an intangible asset could have a significant impact on the company's amortization expense. Where evidence exists that the underlying arrangements have a high likelihood of continued renewal at little or no cost to the company, the intangible asset is assigned an indefinite life and reviewed for impairment on an annual basis. The company reevaluates the useful life determination for intangible assets each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life or an indication of impairment. Management contracts that are managed and operated on a single global platform are reviewed in aggregate as one unit of valuation and are considered interchangeable because investors may freely transfer between funds. Similarly, cash flows generated by new funds added to the global platform are included when determining the fair value of the intangible asset. Definite-lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that their carrying amount may not be recoverable. In addition, management judgment is required to estimate the period over which definite-lived intangible assets will contribute to the company's cash flows and the pattern in which these assets will be consumed. Intangible assets not subject to amortization are tested for impairment annually as of October 1 or more frequently if events or changes in circumstances indicate that the asset might be impaired. The impairment test consists of a comparison of the fair value of an intangible asset with its carrying amount. If the carrying amount of the intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. Fair value is generally determined using an income approach where estimated future cash flows are discounted to arrive at a single present value amount.
Goodwill	Goodwill Goodwill represents the excess of cost over the identifiable net assets of businesses acquired and is recorded in the functional currency of the acquired entity. Goodwill is recognized as an asset and is reviewed for impairment annually as of October 1 and between annual tests when events and circumstances indicate that impairment may have occurred. The company has determined that it has one reporting unit for goodwill impairment testing purposes, the consolidated Invesco Ltd. single operating segment, which is consistent with internal management reporting and management's oversight of operations. The company evaluated the components of its business, which are business units one level below the operating segment level in making this determination. The company's operating segment represents one reporting unit because all of the components are similar due to the common nature of products and services offered, type of clients, methods of distribution, manner in which each component is operated, extent to which they share assets and resources, and the extent to which they support and benefit from common product development efforts. Traditional profit and loss measures are not produced and therefore not reviewed by component management for any of the components. Furthermore, the financial information that is available by component is not sufficient for purposes of performing a discounted cash flow analysis at the component level in order to test goodwill for impairment at that level. As none of the company's components are reporting units, the company has determined that its single operating segment, investment management, is also its single reporting unit. ASU 2011-08 allows the option to first qualitatively assess whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. The company did not utilize this optio n in 2017 a nd performed a quantitative impairment test. The impairment test for goodwill consists of a two-step approach, which is performed at the reporting unit level. If the carrying amount of the reporting unit exceeds its fair value (the first step of the goodwill impairment test), then the second step is performed to determine if goodwill is impaired and to measure the amount of the impairment loss, if any. The second step of the goodwill impairment test compares the implied fair value of goodwill with the carrying amount of goodwill. If the carrying amount of goodwill exceeds the implied fair value of goodwill, an impairment loss is recognized in an amount equal to that excess. The principal method of determining fair value of the reporting unit is an income approach where estimated future cash flows are discounted to arrive at a single present value amount. The discount rate used is derived based on the time value of money and the risk profile of the stream of future cash flows. Recent results and projections based on expectations regarding revenue, expenses, capital expenditure and acquisition earn out payments produce a present value for the reporting unit. The present value produced for the reporting unit is the fair value of the reporting unit. This amount is reconciled to the company's market capitalization to determine an implied control premium, which is compared to an analysis of historical control premiums experienced by peer companies over a long period of time to assess the reasonableness of the fair value of the reporting unit. The company also utilizes a market approach to provide a secondary and corroborative fair value of the reporting unit by using comparable company and transaction multiples to estimate values for our single reporting unit. Discretion and judgment are required in determining whether the transaction data available represents information for companies of comparable nature, scope and size. The results of the secondary market approach to provide a fair value estimate are not combined or weighted with the results of the income approach described above but are used to provide an additional basis to determine the reasonableness of the income approach fair value estimate.
Debt and Financing Costs	Debt and Financing Costs Debt issuance costs related to the issuance of Senior Notes are presented as a deduction from the carrying amount of the related debt liability. Debt issuance costs related to the company's credit facility are presented as a deferred asset within Other Assets on the company's Consolidated Balance Sheets. After initial recognition, debt issuance costs are measured at amortized cost. Finance charges and debt issuance costs are amortized over the term of the debt using the effective interest method. Interest charges are recognized in the Consolidated Statement of Income in the period in which they are incurred.
Revenue Recognition	Revenue Recognition Revenue is measured at the fair value of consideration received or receivable and represents amounts receivable for services provided in the normal course of business, net of discounts, value added tax and other sales-related taxes. Revenue is recognized when there is persuasive evidence of an arrangement, delivery has occurred or services have been provided, collectability is reasonably assured and the revenue can be reliably measured. Revenue represents management, service and distribution, performance and other fees. Revenue is generally accrued over the period for which the service is provided. Investment management fees are derived from providing professional services to manage client accounts and include fees earned from retail mutual funds, investment companies with variable capital (ICVCs), societes d'investissement a capital variable (SICAVs), exchange-traded funds, investment trusts, other collective investment vehicles, and institutional management contracts. Investment management fees for products offered in the retail distribution channel are generally calculated as a percentage of the daily average asset balances and therefore vary as the levels of AUM change resulting from inflows, outflows and market movements. Investment management fees for products offered in the institutional distribution channel are calculated in accordance with the underlying investment management contracts and also vary in relation to the level of client assets managed. Service fees are generated through fees charged to cover several types of expenses, including fund accounting fees and other maintenance costs for mutual funds and SICAVs and administrative fees earned from closed-ended funds. Service fees also include transfer agent fees, which are fees charged to cover the expense of processing client share purchases and redemptions, call center support and client reporting. U.S. distribution fees can include 12b-1 fees earned from certain mutual funds to cover allowable sales and marketing expenses for those funds and also include asset-based sales charges paid by certain mutual funds for a period of time after the sale of those funds. Distribution fees typically vary in relation to the amount of client assets managed. Generally, retail products offered outside of the U.S. do not generate a separate distribution fee, as the quoted management fee rate is inclusive of these services. Performance fee revenues, including carried interests and performance fees related to partnership investments and separate accounts, are generated on certain management contracts when performance hurdles are achieved. Such fee revenues are recorded in operating revenues as of the performance measurement date, when the contractual performance criteria have been met and when the outcome of the transaction can be measured reliably in accordance with Method 1 of ASC Topic 605-20-S99, “Revenue Recognition - Services - SEC Materials.” Cash receipt of performance fees generally occurs after the contractual measurement date; however, the company may receive, from time-to-time, cash distributions of carried interest before the measurement date. Such distributions are reflected as deferred carried interest liabilities within accounts payable and accrued expenses on the Consolidated Balance Sheets. The performance measurement date is defined in each contract in which incentive and performance fee revenue agreements are in effect, and therefore the company has performance fee arrangements that include monthly, quarterly and annual measurement dates. Given the uniqueness of each transaction, performance fee contracts are evaluated on an individual basis to determine if revenues can and should be recognized. The company does not recognize performance fee revenues if there are any future performance contingencies associated with them. As such, these fees are generally not recorded as revenue until the likelihood of claw-back is mathematically improbable. If performance arrangements require repayment of the performance fee for failure to perform during the contractual period, then performance fee revenues are recognized no earlier than the expiration date of these terms. At such point, the associated revenues are considered earned. Performance fees will fluctuate from period to period and may not correlate with general market changes, since most of the fees are driven by relative performance to the respective benchmark rather than by absolute performance. Other revenues include fees derived primarily from transaction commissions earned upon the sale of new investments into certain of our funds and fees earned upon the completion of transactions in our real estate and private equity asset groups. Real estate transaction fees are derived from commissions earned through the buying and selling of properties. Private equity transaction fees include commissions associated with the restructuring of, and fees from providing advice to, portfolio companies held by the funds. These transaction fees are recorded in the Consolidated Financial Statements on the date when the transactions are legally closed. In its capacity as sponsor of UITs, the company earns other revenues related to transactional sales charges resulting from the sale of UIT products and from the difference between the purchase or bid and offer price of securities temporarily held to form new UIT products. These revenues are recorded as other revenues net of concessions to dealers who distribute UITs to investors. Distribution, service and advisory fees that are passed through to external parties are presented separately as expenses in accordance with ASC Topic 605-45, “Revenue Recognition - Principal Agent Considerations.” Third-party distribution, service and advisory expenses include periodic “renewal” commissions paid to brokers and independent financial advisors for the continuing oversight of their clients' assets over the time they are invested and are payments for the servicing of client accounts. Renewal commissions are calculated based upon a percentage of the AUM value and apply to much of the company's non-U.S. retail operations, where they can also take the form of management fee rebates. As discussed above, the revenues from our U.S. retail operations include 12b-1 distribution fees, which are passed through to brokers who sell the funds as third-party distribution expenses along with additional marketing support distribution costs. Both the revenues and the costs are dependent on the underlying AUM of the brokers' clients. Third-party distribution expenses also include the amortization of upfront commissions paid to broker-dealers for sales of fund shares with a contingent deferred sales charge (a charge levied to the investor for client redemption of AUM within a certain contracted period of time). The distribution commissions are amortized over the redemption period. Also included in third-party distribution, service and advisory expenses are sub-transfer agency fees that are paid to third parties for processing client share purchases and redemptions, call center support and client reporting. Interest income is accrued on interest-bearing assets. Dividend income from investments is recognized on the ex-dividend date.
Management and Investment Advisory Fees, Policy [Policy Text Block]	Money Market Fee Waivers The company is currently voluntarily providing yield support waivers of its management fees on certain money market funds to ensure that they maintain a minimum level of daily net investment income. For the year ended December 31, 2017 , yield support waivers resulted in a reduction of management and service and distribution fees of approximately $4.7 million . During the year ended December 31, 2017, approximately 70.0% of yield support waivers were offset by a reduction in third party distribution, service and advisory expenses, resulting in a net waiver of $1.4 million . The company may increase or decrease the level of fee waivers in future periods.
Share-Based Compensation	Share-Based Compensation The company issues equity-settled share-based awards to certain employees, which are measured at fair value at the date of grant. The fair value determined at the grant date is expensed, based on the company's estimate of shares that will eventually vest, on a straight-line or accelerated basis over the vesting period. The initial forfeiture rate applied to most grants is 3% per year, based upon the company's historical experience with respect to employee turnover. Fair value for the share awards representing equity interests identical to those associated with shares traded in the open market is determined using the market price at the date of grant.
Deferred Compensation	Deferred Compensation The company issues deferred cash awards to certain employees which are linked in value to investment products. The employees may earn a return linked to the appreciation or depreciation of specified investments, typically the funds they manage. The company currently hedges economically the exposure to market movements on certain of its deferred compensation plans by holding the investments on its balance sheet and through a total return swap financial instrument. The company recognizes as compensation expense the value of the liability to employees, including the appreciation or depreciation of the liability, over the award's vesting period in proportion to the vested amount of the award. The company immediately recognizes the full value of the related investment, and any subsequent appreciation or depreciation of the investment, in Other gains and losses, net.
Pensions	Pensions For defined contribution plans, contributions payable related to the accounting period are charged to the income statement. For defined benefit plans, the cost of providing benefits is separately determined for each plan using the projected unit credit method, based on actuarial valuations performed at each balance sheet date. The company's annual measurement date is December 31. A portion of actuarial gains and losses is recognized through the income statement if the net cumulative unrecognized actuarial gain or loss at the end of the prior period exceeds the greater of 10.0% of the present value of the defined benefit obligation (before deducting plan assets) at that date and 10.0% of the fair value of any plan assets.
Advertising Costs	Advertising Costs The company expenses the cost of all advertising and promotional activities as incurred. The company incurred advertising costs of $37.2 million for the year ended December 31, 2017 ( December 31, 2016 : $32.7 million ; December 31, 2015 : $35.4 million ). These amounts are included in marketing expenses in the Consolidated Statements of Income.
Leases	Leases The company complies with lease accounting in accordance with ASC Topic 840, "Leases.” Under operating leases, where the lessor retains substantially all the risks and benefits of ownership of the asset, rental payments, as well as any step rent provisions specified in lease agreements, are aggregated and charged evenly to expense over the lease term beginning on the date of initial possession or the effective date of the lease agreement. Maintenance, utility, and tax costs included in lease agreements are expensed in the period incurred. Rental payments dependent upon an existing index or rate are included in the minimum lease payments based on the index or rate in effect at the inception of the lease and are recognized on a straight-line basis over the minimum lease term. Changes in rental payments that result from subsequent changes in the index or rate are expensed in the period incurred. Capital improvement funding and other lease concessions provided by the landlord are recorded as a deferred liability and are amortized evenly over the lease term as a reduction of rental expense. The company accounts for lease termination costs in accordance with ASC Topic 420, “Exit or Disposal Cost Obligations,” which requires that (1) a liability for costs to terminate a contract before the end of its term shall be recognized at the time termination occurs and measured at fair value and (2) a liability for costs that will continue to be incurred under a contract for its remaining term without economic benefit to the company be recognized and measured at its fair value when the company ceases to use the right conveyed by the contract, net of estimated sublease rentals that could reasonably be obtained even if the company does not anticipate entering into any subleasing arrangements.
Taxation	Taxation Income taxes are provided for in accordance with ASC Topic 740, “Income Taxes” (ASC Topic 740). Deferred tax assets and liabilities are recorded for temporary differences between the tax basis of assets and liabilities and the reported amounts in the Consolidated Financial Statements, using the statutory tax rates in effect for the year in which the differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the results of operations in the period that includes the enactment date. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets to the amount that is more likely than not to be realized. The company reports a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. The company recognizes interest and penalties, if any, related to unrecognized tax benefits in income tax expense. Certain income tax effects of the 2017 Tax Act are reflected in our financial results in accordance with Staff Accounting Bulletin No. 118 (SAB 118), which provides SEC staff guidance regarding the application of ASC Topic 740 in the reporting period in which the 2017 Tax Act became law. See also Item 8, Financial Statements and Supplementary Data - in Note 15, "Taxation," for further details and additional discussion on estimated amounts recorded as of December 31, 2017 for the 2017 Tax Act.
Earnings Per Share	Earnings Per Share Basic and diluted earnings per share are computed using the two-class method, which treats unvested restricted shares as if they were a separate class of shares. Under the two-class method, net income attributable to Invesco Ltd. is adjusted for the allocation of earnings to the unvested restricted shares. In addition, the weighted-average shares outstanding is adjusted for unvested restricted shares. There is no difference between the calculated earnings per share amounts attributable to Invesco Ltd. and the calculated earnings per share amounts under the two-class method.
Comprehensive Income	Comprehensive Income The company's other comprehensive income/(loss) consists of changes in unrealized gains and losses on investment securities classified as available-for-sale, the company's share of other comprehensive income of equity method investments, reclassification adjustments for realized gains/(losses) on those investment securities classified as available-for-sale, foreign currency translation adjustments and employee benefit plan liability adjustments. Such amounts are recorded net of applicable taxes.
Dividends to Shareholders	Dividends to Shareholders Dividends to shareholders are recognized on the declaration date. Dividends are declared and paid on a quarterly basis.
Translation of Foreign Currencies	Translation of Foreign Currencies Transactions in foreign currencies (currencies other than the functional currencies of the company's subsidiaries) are recorded at the rates of exchange prevailing on the dates of the transactions. At each balance sheet date, monetary assets and liabilities that are denominated in foreign currencies are remeasured into the functional currencies of the company's subsidiaries at the rates prevailing at the balance sheet date. Gains and losses arising on revaluation are included in the Consolidated Statements of Income. The company's reporting currency and the functional currency of the Parent is U.S. Dollars. On consolidation, the assets and liabilities of company subsidiary operations whose functional currencies are currencies other than the U.S. Dollar (“foreign” operations) are translated at the rates of exchange prevailing at the balance sheet date. Consolidated Statements of Income amounts are translated at the weighted average rates for the year, which approximate actual exchange rates. Exchange differences arising on the translation of the net assets of foreign operations are taken directly to accumulated other comprehensive income in equity until the disposal of the net investment, at which time they are recognized in the Consolidated Statements of Income. Goodwill and other fair value adjustments arising on acquisition of a foreign entity are treated as assets and liabilities of the foreign entity and are translated at rates of exchange prevailing at the balance sheet date. The company has in the past purchased several put option contracts to hedge economically foreign currency risk on the translation of its Pound Sterling- and Euro-denominated earnings into U.S. Dollars. See Note 2 , "Fair Value of Assets and Liabilities," for additional information. Additionally, the company may, from time to time, designate certain intercompany debt as non-derivative net investment hedging instruments against foreign currency exposure related to its net investment in foreign operations. See Note 10 , "Other Comprehensive Income/(Loss)." In the management of its cross-border fund operations, foreign currency forward and swap contracts are purchased daily to hedge against foreign exchange rate movements during the four-day client money settlement period. Certain CIP may also utilize such instruments.
Accounting Pronouncements Recently Adopted and Pending Accounting Pronouncements	Accounting Pronouncements Recently Adopted and Pending Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update 2014-09, “Revenue from Contracts with Customers” (ASU 2014-09) which revises revenue recognition criteria and expands disclosure requirements. This new guidance will be effective for interim and annual reporting periods beginning after December 15, 2017. The company has elected to implement this new accounting standard on January 1, 2018 using the modified retrospective transition method applied to those contracts which were not completed as of that date. Under this method, entities are required to report any effect from adoption as a cumulative effect adjustment to retained earnings at the adoption date. The company does not currently expect to report any adjustments to opening retained earnings and does not expect that the new standard will have a material impact on net income or earnings per share measures. The underlying premise of the new guidance requires the use of a five step model to determine the amount of revenue that reflects the consideration that the company is entitled to for the transfer of services to customers and the timing of such revenue recognition. In addition, ASU 2014-09 also requires certain costs to obtain and fulfill contracts with customers to be capitalized, if they meet certain criteria. The company does not anticipate capitalizing any contract costs. A key part of management’s implementation efforts included a detailed review of the terms and conditions of a sample of revenue contracts covering a broad range of products across geographic locations. Based upon management’s findings, the company does not anticipate a change in the timing of revenue recognition for investment management and service and distribution fee revenues. The timing of recognition for performance fees (including carried interest) is driven by the terms of each performance fee arrangement. Management has determined that there will not be a cumulative adjustment to opening retained earnings related to performance fee revenues. Due to the revised criteria related to whether or not the company is acting as a principal or agent, the company expects a change in presentation related to certain costs incurred to fulfill its performance obligations, which are currently presented on a net basis and will be presented as an expense under the new guidance. Furthermore, Investment management fee revenues will be reduced by certain amounts that have previously been reported in Third-party distribution, service and advisory expense. In February 2015, the FASB issued Accounting Standard Update 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis.” This standard modifies existing consolidation guidance for reporting organizations that are required to evaluate whether they should consolidate certain legal entities. The company adopted ASU 2015-02 on January 1, 2016 using the modified retrospective approach, which did not require the restatement of prior periods to conform to the post-adoption presentation. The impacts of the adoption of ASU 2015-02 on January 1, 2016 were as follows: • The company consolidated CIP with total assets and liabilities/equity of $458.5 million . The company deconsolidated CIP with total assets and total liabilities and equity of $3,170.6 million , including CLOs of $2,366.5 million . • VOE partnership entities (consolidated private equity and fund-of-fund entities) became VIEs upon the adoption and were deconsolidated, along with certain VIE partnership entities. • The adoption resulted in the consolidation of certain investment products which became VIEs upon adoption and which were not previously consolidated. • The funds consolidated in prior periods as Consolidated Sponsored Investment Products, "CSIP," became VIEs. Accordingly, with effect from January 1, 2016, the consolidation of all VIEs is presented in the aggregate as part of CIP. See Note 19 “Consolidated Investment Products.” In January 2016, the FASB issued Accounting Standards Update 2016-01, “Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities” (ASU 2016-01). The standard amends certain aspects of recognition, measurement, presentation, and disclosure of financial assets and liabilities. ASU 2016-01 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017 and, in general, requires a modified retrospective approach to adoption. The standard is effective for the company January 1, 2018. The standard requires that all equity investments, other than those accounted for as equity method investments, be measured at fair value with changes recognized in income. The standard also requires that all net unrealized holding gains related to available-for-sale equity investments be reclassified from accumulated other comprehensive income into retained earnings at the date of adoption. At December 31, 2017 , the company held available-for-sale seed money investments of $69.3 million ; net unrealized holding gains on these investments were $4.2 million . Based on the company’s assessment of the standard to date, no other significant changes are anticipated. In February 2016, the FASB issued Accounting Standards Update 2016-02, “Leases” (ASU 2016-02). The standard requires that lessees recognize lease assets and lease liabilities on the balance sheet for all leases with a lease term greater than 12 months. ASU 2016-02 is effective for fiscal years and interim periods within those years beginning after December 15, 2018 and requires a modified retrospective approach to adoption. Early adoption is permitted; however, the Company plans to adopt ASU 2016-02 on January 1, 2019. The company is currently evaluating the potential impact of this standard which includes performing a review of a sample of lease arrangements. In March 2016, the FASB issued Accounting Standards Update 2016-09, “Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting” (ASU 2016-09). The standard is intended to simplify aspects of the accounting for share-based payment transactions, including income tax impacts, classification on the statement of cash flows, and forfeitures. The company adopted ASU 2016-09 on January 1, 2017. One of the impacts of the new rules is that excess tax benefits and tax deficiencies related to vested awards are no longer recorded in additional paid-in-capital but rather as an income tax expense or benefit. This provision requires a prospective approach to adoption. In the year ended December 31, 2017 , the recognition of excess tax benefits reduced our income tax provision by $3.8 million . Another change resulting from the adoption of ASU 2016-09 relates to the presentation of these excess tax benefits and tax deficiencies in the Consolidated Statement of Cash Flows. The standard requires that excess tax benefits and tax deficiencies be shown as operating cash flows within the Consolidated Statements of Cash Flows; previously, the company reported these cash flow activities as financing cash flows. The company elected to use a prospective approach to adoption related to this provision and in the year ended December 31, 2017 , $3.8 million cash inflows were included within the increase/(decrease) in payables as an operating cash flow in the Consolidated Statements of Cash Flows. ASU 2016-09 requires that employee taxes paid when shares are withheld for tax withholding purposes be reported as a financing activity in the Consolidated Statements of Cash Flows. The company has retrospectively adopted this change and included $63.8 million in financing activities for the year ended December 31, 2017 ( December 31, 2016 : $42.0 million ; December 31, 2015 : $74.9 million ). Additionally, the new rules allow companies to elect to continue to account for forfeitures using an estimate or instead to elect to account for forfeitures as they occur. The company elected to continue to account for forfeitures using an estimate. The company anticipates fluctuations in its effective tax rate as a result of the excess tax benefits or tax deficiencies being recorded to the income tax provision, particularly in the first quarter of each year when annual share awards vest. In June 2016, the FASB issued Accounting Standards Update 2016-13, “Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments” (ASU 2016-13). ASU 2016-13 amends guidance on reporting credit losses for assets measured at amortized cost and available for sale securities. ASU 2016-13 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019 and requires a modified retrospective approach to adoption. Early adoption in fiscal years, and interim periods within those years, beginning after December 15, 2018 is permitted. The company is currently evaluating the potential impact of this standard. In August 2016, the FASB issued Accounting Standards Update 2016-15, “Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments” (ASU 2016-15). The standard addresses eight specific cash flow issues to reduce diversity in practice in how certain cash receipts and cash payments are presented on the Statements of Cash Flows. ASU 2016-15 is effective for fiscal years and interim periods within those years beginning after December 15, 2017 and the amendment requires a retrospective approach to adoption. The standard requires that an entity make an accounting policy election to classify distributions received from equity method investees using either the cumulative approach or the nature of the distribution approach. The company has elected to use the cumulative approach and continues to assess prior distributions received for the appropriate classification in the statement of cash flows. In October 2016, the FASB issued Accounting Standards Update 2016-16, “Income Taxes: Intra-Entity Transfers of Assets Other than Inventory” (ASU 2016-16). The standard will require the recognition of income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs, instead of deferring the income tax recognition until the asset is sold to an outside party. ASU 2016-16 is effective for fiscal years and interim periods within those years beginning after December 15, 2017. The amendments require a modified retrospective approach to adoption. The company does not expect this standard to have a material impact on the company's financial condition, results of operations or cash flows. In October 2016, the FASB issued Accounting Standards Update 2016-17, “Consolidation: Interests Held through Related Parties That Are under Common Control” (ASU 2016-17). The standard addresses how a reporting entity determines if it satisfies the characteristics of a primary beneficiary of a VIE and which party within a group is considered the primary beneficiary. The company adopted ASU 2016-17 on January 1, 2017 and determined that this guidance did not materially change the company's consolidation conclusions. In November 2016, the FASB issued Accounting Standards Update 2016-18, “Statement of Cash Flows: Restricted Cash” (ASU 2016-18). The standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU 2016-18 is effective for fiscal years and interim periods within those years beginning after December 15, 2017 and requires a retrospective approach to adoption. The standard is effective for the company January 1, 2018. For the year ended December 31, 2017 , the change in cash held by CIP increased cash provided by operations by $226.2 million (year-ended December 31, 2016 : the change in cash held by CIP decreased cash provided by operations by $509.4 million ). After the adoption of ASU 2016-18, these changes in CIP cash will no longer be presented as a component of the company's cash provided by operations. Instead, the changes in CIP cash will form part of the reconciliation of corporate cash and CIP cash at the end of the Consolidated Statements of Cash Flows. The adoption of this standard does not impact corporate cash and cash equivalents but is a change in presentation within the Consolidated Statements of Cash Flows. In January 2017, the FASB issued Accounting Standards Update 2017-01, “Business Combinations: Clarifying the Definition of a Business” (ASU 2017-01). The standard clarifies the definition of a business and adds guidance to assist entities when evaluating whether transactions should be accounted for as acquisitions or disposals of assets or as businesses. The standard provides an initial screen to determine whether a set of assets and activities qualifies as a business or as a set of assets. ASU 2017-01 is effective for fiscal years and interim periods within those years beginning after December 15, 2017. The amendments require a prospective approach to adoption. The impact of this standard will depend on the specific terms and conditions of an acquisition or disposition of assets or businesses. The company will apply the new standard to all applicable transactions in the 2018 fiscal year and beyond. In January 2017, the FASB issued Accounting Standards Update 2017-04, “Intangibles-Goodwill and Other: Simplifying the Test for Goodwill Impairment” (ASU 2017-04). The standard simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Under the amendments of ASU 2017-04, an entity should perform its goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, but the loss cannot exceed the total amount of goodwill allocated to the reporting unit. ASU 2017-04 is effective for fiscal years and interim periods within those years beginning after December 15, 2019. The amendments require a prospective approach to adoption and early adoption is permitted for interim or annual goodwill impairment tests. The company is currently evaluating the impact of this standard. In February 2017, the FASB issued Accounting Standards Update 2017-05, “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets: Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets” (ASU 2017-05). The standard clarifies the scope of accounting for gains and losses from the derecognition of nonfinancial assets and adds guidance for partial sales of nonfinancial assets. ASU 2017-05 is effective for fiscal years and interim periods within those years beginning after December 15, 2017 and must be adopted at the same time as ASU 2014-09. The amendments allow either a retrospective or modified retrospective approach to adoption. The company does not expect this standard to have a material impact on the company's financial condition, results of operations or cash flows. In March 2017, the FASB issued Accounting Standard Update 2017-07, “Compensation-Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” (ASU 2017-07). The amendments require that an employer disaggregate the service cost component from the other components of net benefit cost. The amendments also provide guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow that only the service cost component of net benefit cost is eligible for capitalization. ASU 2017-07 is effective for fiscal years and interim periods within those years beginning after December 15, 2017. The amendments require primarily a retrospective approach to adoption. The application of the new rules will result in the reclassification of pension related costs within the Consolidated Statements of Income and no impact to the results of operations.

Fair Value Of Assets And Liab31

Fair Value Of Assets And Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Of Financial Instruments Held By Consolidated Investments	The carrying value and fair value of financial instruments is presented in the below summary table. The fair value of financial instruments held by CIP are presented in Note 19 , "Consolidated Investment Products". December 31, 2017 December 31, 2016 $ in millions Carrying Value Fair Value Carrying Value Fair Value Cash and cash equivalents 2,006.4 2,006.4 1,328.0 1,328.0 Available-for-sale investments 85.2 85.2 154.0 154.0 Trading investments 277.3 277.3 329.6 329.6 Foreign time deposits * 28.6 28.6 26.9 26.9 Assets held for policyholders 12,444.5 12,444.5 8,224.2 8,224.2 Policyholder payables * (12,444.5 ) (12,444.5 ) (8,224.2 ) (8,224.2 ) Put option contracts 0.8 0.8 21.8 21.8 UIT-related financial instruments sold, not yet purchased (1.4 ) (1.4 ) (6.0 ) (6.0 ) Contingent consideration liability (57.4 ) (57.4 ) (78.2 ) (78.2 ) Long-term debt * (2,075.8 ) (2,258.1 ) (2,102.4 ) (2,206.5 ) ____________ * These financial instruments are not measured at fair value on a recurring basis. See the indicated footnotes for additional information about the carrying and fair values of these financial instruments. Foreign time deposits are measured at cost plus accrued interest, which approximates fair value, and are accordingly classified as Level 2 securities.
Tri-Level Hierarchy, Carrying Value	The following table presents, for each of the hierarchy levels described above, the carrying value of the company's assets and liabilities, including major security type for equity and debt securities, which are measured at fair value on the company's Consolidated Balance Sheet as of December 31, 2017 : As of December 31, 2017 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds 875.5 875.5 — — Investments:* Available-for-sale: Seed money 69.3 69.3 — — CLOs 6.0 — 6.0 — Other debt securities 9.9 — — 9.9 Trading investments: Investments related to deferred compensation plans 92.3 92.3 — — Seed money 173.7 173.7 — — Other equity securities 8.9 8.9 — — UIT-related equity and debt securities: Corporate equities 2.0 2.0 — — UITs 0.4 0.4 — — Assets held for policyholders 12,444.5 12,444.5 — — Put option contracts 0.8 — 0.8 — Total 13,683.3 13,666.6 6.8 9.9 Liabilities: UIT-related financial instruments sold, not yet purchased: Exchange traded funds (1.4 ) (1.4 ) — — Contingent consideration liability (57.4 ) — — (57.4 ) Total (58.8 ) (1.4 ) — (57.4 ) ____________ * Foreign time deposits of $28.6 million are excluded from this table. Equity and other investments of $277.3 million and $6.2 million , respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards. The following table presents, for each of the hierarchy levels described above, the carrying value of the company's assets and liabilities, including major security type for equity and debt securities, which are measured at fair value on the company's Consolidated Balance Sheet as of December 31, 2016 : As of December 31, 2016 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Assets: Cash equivalents: Money market funds 476.2 476.2 — — Investments:* Available-for-sale: Seed money 127.9 127.9 — — CLOs 12.9 — — 12.9 Other debt securities 13.2 — — 13.2 Trading investments: Investments related to deferred compensation plans 170.5 170.5 — — Seed money 121.9 121.9 — — Other equity securities 30.4 30.4 — — UIT-related equity and debt securities: Corporate equities 1.2 1.2 — — UITs 5.6 5.6 — — Assets held for policyholders 8,224.2 8,224.2 — — Put option contracts 21.8 — 21.8 — Total 9,205.8 9,157.9 21.8 26.1 Liabilities: UIT-related financial instruments sold, not yet purchased: Exchange traded funds (5.2 ) (5.2 ) — — U.S. treasury securities (0.8 ) (0.8 ) — — Contingent consideration liability (78.2 ) — — (78.2 ) Total (84.2 ) (6.0 ) — (78.2 ) ____________ * Foreign time deposits of $26.9 million are excluded from this table. Equity and other investments of $279 million and $5.8 million , respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards.
Reconciliation of Balance, Fair Value Measurement, Level 3	* Foreign time deposits of $26.9 million are excluded from this table. Equity and other investments of $279 million and $5.8 million , respectively, are also excluded from this table. These investments are not measured at fair value, in accordance with applicable accounting standards. The following table shows a reconciliation of the beginning and ending fair value measurements for level 3 assets and liabilities during the year ended December 31, 2017 and December 31, 2016 , which are valued using significant unobservable inputs: For the year ended December 31, 2017 For the year ended December 31, 2016 $ in millions Contingent Consideration Liability CLOs Other Debt Securities Contingent Consideration Liability CLOs Other Debt Securities Beginning balance (78.2 ) 12.9 13.2 (83.9 ) 1.4 5.9 Adjustment for adoption of ASU 2015-02 — — — — 11.5 — Beginning balance, as adjusted (78.2 ) 12.9 13.2 (83.9 ) 12.9 5.9 Purchases/acquisitions — — 7.4 — — 21.4 Returns of capital — — — — (3.0 ) — Net unrealized gains and losses included in other gains and losses* 7.6 — (3.2 ) (7.4 ) — — Net unrealized gains and losses included in accumulated other comprehensive income/(loss) * — — — — 3.0 — Disposition/settlements 13.2 — (7.5 ) 13.1 — (14.1 ) Transfer from level 3 to level 2 — (12.9 ) — — — — Ending balance (57.4 ) — 9.9 (78.2 ) 12.9 13.2 ____________ * These unrealized gains and losses are attributable to balances still held at the respective year ends.

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Investments [Abstract]
Marketable Securities [Table Text Block]	$ in millions December 31, 2017 December 31, 2016 Available-for-sale investments: Seed money 69.3 127.9 CLOs 6.0 12.9 Other debt securities 9.9 13.2 Trading investments: Investments related to deferred compensation plans 92.3 170.5 Seed money 173.7 121.9 UIT-related equity and debt securities 2.4 6.8 Other equity securities 8.9 30.4 Equity method investments 277.3 279.0 Foreign time deposits 28.6 26.9 Other 6.2 5.8 Total investments 674.6 795.3
Realized Gains Losses Available-For-Sale Securities	Realized gains and losses recognized in the Consolidated Statements of Income during the year from investments classified as available-for-sale are as follows: 2017 2016 2015 $ in millions Proceeds from Sales Gross Realized Gains Gross Realized Losses Proceeds from Sales Gross Realized Gains Gross Realized Losses Proceeds from Sales Gross Realized Gains Gross Realized Losses Seed money 62.5 4.3 (1.5 ) 42.7 1.5 (1.6 ) 48.1 2.2 (0.2 ) CLOs 7.1 1.9 — 3.0 — — 2.6 0.5 — Other debt securities 9.9 2.5 — 13.6 — (0.5 ) 0.4 — — 79.5 8.7 (1.5 ) 59.3 1.5 (2.1 ) 51.1 2.7 (0.2 )
Gross Unrealized Holding Gains And Losses Recognized In Other Accumulated Comprehensive Income From Available-For-Sale Investments	Gross unrealized holding gains and losses recognized in other accumulated comprehensive income from available-for-sale investments are presented in the table below: December 31, 2017 December 31, 2016 $ in millions Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Seed money 65.1 5.5 (1.3 ) 69.3 127.2 6.8 (6.1 ) 127.9 CLOs 4.9 1.1 — 6.0 9.2 3.7 — 12.9 Other debt securities 9.9 — — 9.9 13.2 — — 13.2 79.9 6.6 (1.3 ) 85.2 149.6 10.5 (6.1 ) 154.0
Breakdown Of Available-For-Sale Investments with Unrealized Losses	The following table provides a breakdown of the unrealized losses. December 31, 2017 December 31, 2016 $ in millions Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Less than 12 months 9.4 (0.8 ) 1.9 (0.2 ) 12 months or greater 15.0 (0.5 ) 56.4 (5.9 ) Total 24.4 (1.3 ) 58.3 (6.1 )
Held-to-maturity Securities	Available-for-sale debt securities as of December 31, 2017 by maturity, are set out below: Available-for-Sale (Fair Value) Less than one year 9.9 One to five years 2.8 Five to ten years 3.2 Greater than ten years — Total available-for-sale 15.9
Summary Of Company's Investment In Joint Ventures And Affiliates	Following are the company's investments in joint ventures and affiliates, which are accounted for using the equity method and are recorded as investments on the Consolidated Balance Sheets: Name of Company Country of Incorporation % Voting Interest Owned Huaneng Invesco WLR (Beijing) Investment Fund Management Company Ltd. China 50.0% Invesco Great Wall Fund Management Company Limited China 49.0% Pocztylion - ARKA Poland 29.3%
Summary of company's voting control in entities where it has noncontrolling interest	The company owns 100% of the voting control of its subsidiary entities, directly or indirectly, with the exception of the following entities, which are consolidated with resulting noncontrolling interests: Name of Company Country of Incorporation % Voting Interest Owned VV Immobilien Verwaltungs und Beteiligungs GmbH Germany 70.0% VV Immobilien Verwaltungs GmbH Germany 70.0% HVH Immobilien und Beteiligungs GmbH Germany 70.0%

Property, Equipment And Softw33

Property, Equipment And Software (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The following is a summary of property, equipment and software: $ in millions December 31, 2017 December 31, 2016 Technology and Other Equipment 261.0 242.3 Software 621.9 467.4 Land and Buildings 87.5 68.2 Leasehold Improvements 204.4 210.9 Work in Process 44.8 117.0 Property, Equipment and Software, Gross 1,219.6 1,105.8 Less: Accumulated Depreciation (728.9 ) (641.1 ) Property, Equipment and Software, Net 490.7 464.7

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Schedule of Finite-Lived Intangible Assets by Major Class	The following table presents the major classes of the company's intangible assets at December 31 , 2017 and 2016 : $ in millions Gross Book Value Accumulated Amortization Net Book Value December 31, 2017 Management contracts - indefinite-lived 1,523.3 N/A 1,523.3 Management contracts - finite-lived 68.8 (66.3 ) 2.5 Customer relationships 40.0 (25.3 ) 14.7 Other 27.6 (9.4 ) 18.2 Total 1,659.7 (101.0 ) 1,558.7 December 31, 2016 Management contracts - indefinite-lived 1,363.6 N/A 1,363.6 Management contracts - finite-lived 67.7 (56.6 ) 11.1 Customer relationships 40.0 (21.9 ) 18.1 Other 9.8 (3.2 ) 6.6 Total 1,481.1 (81.7 ) 1,399.4
Schedule Of Future Amortization Expense Of Intangible Assets	Estimated amortization expense for each of the five succeeding fiscal years based upon the company's intangible assets at December 31, 2017 is as follows: $ in millions Years Ended December 31, Estimated Amortization Expense 2018 15.6 2019 8.1 2020 4.7 2021 4.7 2022 2.3

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill [Abstract]
Schedule of Goodwill	The table below details changes in the goodwill balance: $ in millions Net Book Value January 1, 2017 6,129.2 Business combinations 193.3 Foreign exchange 268.2 December 31, 2017 6,590.7 January 1, 2016 6,175.7 Business combinations 135.7 Foreign exchange (182.2 ) December 31, 2016 6,129.2

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Schedule of Other Liabilities	The table below details the components of other liabilities: As of $ in millions December 31, 2017 December 31, 2016 Compensation and benefits 101.2 92.8 Accrued bonus and deferred compensation 594.9 561.5 Accrued compensation and benefits 696.1 654.3 Accruals and other liabilities 302.3 280.6 Deferred carried interest 60.4 87.7 Contingent consideration liability 57.4 78.2 Accounts payable 320.1 274.3 Income taxes payable 155.5 91.6 Accounts payable and accrued expenses 895.7 812.4

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt Instruments	The disclosures below include details of the company's debt. Debt of CIP is detailed in Note 19 , “Consolidated Investment Products.” December 31, 2017 December 31, 2016 $ in millions Carrying Value** Fair Value Carrying Value** Fair Value Floating rate credit facility expiring August 11, 2022 — — 28.7 28.7 Unsecured Senior Notes*: $600 million 3.125% - due November 30, 2022 596.9 608.8 596.3 604.7 $600 million 4.000% - due January 30, 2024 594.0 634.7 593.2 625.3 $500 million 3.750% - due January 15, 2026 495.1 515.0 494.5 506.4 $400 million 5.375% - due November 30, 2043 389.8 499.6 389.7 441.4 Long-term debt 2,075.8 2,258.1 2,102.4 2,206.5 ____________ * The company's senior note indentures contain certain restrictions on mergers or consolidations. Beyond these items, there are no other restrictive covenants in the indentures. ** The difference between the principal amounts and the carrying values of the senior notes in the table above reflect the unamortized debt issuance costs and discounts.
Analysis Of Borrowings By Maturity	Analysis of Borrowings by Maturity: $ in millions December 31, 2017 2022 596.9 2024 594.0 2026 495.1 2043 389.8 Long-term debt 2,075.8

Share Capital (Tables)

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Movements In Shares Issued And Outstanding	he number of common shares and common share equivalents issued are represented in the table below: In millions December 31, 2017 December 31, 2016 December 31, 2015 Common shares issued 490.4 490.4 490.4 Less: Treasury shares for which dividend and voting rights do not apply (83.3 ) (86.6 ) (72.9 ) Common shares outstanding 407.1 403.8 417.5
Movements In Treasury Shares	Movements in Treasury Shares comprise: Year ended In millions December 31, 2017 December 31, 2016 December 31, 2015 Beginning balance 95.9 81.3 69.4 Acquisition of common shares 1.9 19.6 17.4 Distribution of common shares (5.2 ) (4.7 ) (5.2 ) Common shares distributed to meet ESPP obligation (0.2 ) (0.3 ) (0.1 ) Common shares distributed to meet option exercises — — (0.2 ) Ending balance 92.4 95.9 81.3

Other Comprehensive Income_(L39

Other Comprehensive Income/(Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income	The components of accumulated other comprehensive income/(loss) were as follows: 2017 $ in millions Foreign currency translation Employee benefit plans Equity method investments Available-for-sale investments Total Other comprehensive income/(loss), net of tax: Currency translation differences on investments in foreign subsidiaries 389.4 — — — 389.4 Actuarial gain/(loss) related to employee benefit plans — 21.1 — — 21.1 Settlement related to employee benefit plans — 5.9 — — 5.9 Reclassification of actuarial (gains)/losses into employee compensation expenses — 2.5 — — 2.5 Share of other comprehensive income/(loss) of equity method investments — — (0.5 ) — (0.5 ) Unrealized gains/(losses) on available-for-sale investments — — — 5.1 5.1 Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses, net — — — (5.4 ) (5.4 ) Other comprehensive income/(loss) 389.4 29.5 (0.5 ) (0.3 ) 418.1 Beginning balance (679.9 ) (139.2 ) 4.8 5.0 (809.3 ) Other comprehensive income/(loss) 389.4 29.5 (0.5 ) (0.3 ) 418.1 Ending balance (290.5 ) (109.7 ) 4.3 4.7 (391.2 ) 2016 $ in millions Foreign currency translation Employee benefit plans Equity method investments Available-for-sale investments Total Other comprehensive income/(loss) net of tax: Currency translation differences on investments in foreign subsidiaries (314.1 ) — — — (314.1 ) Actuarial gain/(loss) related to employee benefit plans — (39.5 ) — — (39.5 ) Prior service credit related to employee benefit plans — (3.1 ) — — (3.1 ) Settlement related to employee benefit plans — (5.5 ) — — (5.5 ) Reclassification of prior service (credit)/cost into employee compensation expense — (7.0 ) — — (7.0 ) Reclassification of actuarial (gains)/losses into employee compensation expenses — 1.5 — — 1.5 Share of other comprehensive income/(loss) of equity method investments — — (1.1 ) — (1.1 ) Unrealized gains/(losses) on available-for-sale investments — — — 5.2 5.2 Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses, net — — — 0.3 0.3 Other comprehensive income/(loss) (314.1 ) (53.6 ) (1.1 ) 5.5 (363.3 ) Beginning balance (365.8 ) (85.6 ) 5.9 (0.5 ) (446.0 ) Other comprehensive income/(loss) (314.1 ) (53.6 ) (1.1 ) 5.5 (363.3 ) Ending balance (679.9 ) (139.2 ) 4.8 5.0 (809.3 ) 2015 $ in millions Foreign currency translation Employee benefit plans Equity method investments Available-for-sale investments Total Other comprehensive income/(loss) net of tax: Currency translation differences on investments in foreign subsidiaries (493.9 ) — — — (493.9 ) Actuarial gain/(loss) related to employee benefit plans — 11.1 — — 11.1 Reclassification of prior service (credit)/cost into employee compensation expense — (7.2 ) — — (7.2 ) Reclassification of actuarial (gains)/losses into employee compensation expenses — 2.2 — — 2.2 Share of other comprehensive income/(loss) of equity method investments — — (0.6 ) — (0.6 ) Unrealized gains/(losses) on available-for-sale investments — — — (6.0 ) (6.0 ) Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses, net — — — (0.4 ) (0.4 ) Other comprehensive income/(loss) (493.9 ) 6.1 (0.6 ) (6.4 ) (494.8 ) Beginning balance 128.1 (91.7 ) 6.5 5.9 48.8 Other comprehensive income/(loss) (493.9 ) 6.1 (0.6 ) (6.4 ) (494.8 ) Ending balance (365.8 ) (85.6 ) 5.9 (0.5 ) (446.0 )

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Movements Of Share Awards	Movements on share awards priced in U.S. Dollars during the years ended December 31, are detailed below: 2017 2016 2015 Millions of shares, except fair values Time-Vested Performance-Vested Weighted Average Grant Date Fair Value ($) Time-Vested Performance-Vested Time- Vested Performance-Vested Unvested at the beginning of year 12.1 0.8 31.22 10.4 0.6 11.5 0.5 Granted during the year 5.3 0.3 32.23 6.5 0.4 4.1 0.3 Forfeited during the year (0.4 ) — 31.51 (0.3 ) — (0.2 ) — Vested and distributed during the year (5.0 ) (0.2 ) 31.53 (4.5 ) (0.2 ) (5.0 ) (0.2 ) Unvested at the end of the year 12.0 0.9 31.52 12.1 0.8 10.4 0.6

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits, Description [Abstract]
Schedule of defined benefit plan obligations and assets	The amounts included in the Consolidated Balance Sheets arising from the company's obligations and plan assets in respect of its defined benefit retirement plans are as follows: Retirement Plans $ in millions 2017 2016 Benefit obligation (548.6 ) (521.2 ) Fair value of plan assets 486.9 424.1 Funded status (61.7 ) (97.1 ) Amounts recognized in the Consolidated Balance Sheets: Other assets 3.6 3.4 Accrued compensation and benefits (65.3 ) (100.5 ) Funded status (61.7 ) (97.1 )
Changes in defined benefit plan obligations	Changes in the benefit obligations were as follows: Retirement Plans $ in millions 2017 2016 January 1 521.2 490.7 Service cost 2.3 4.6 Interest cost 14.1 16.5 Actuarial (gains)/losses 3.3 102.4 Exchange difference 51.7 (73.5 ) Benefits paid (9.0 ) (13.8 ) Plan amendments — 4.1 Curtailment — (9.8 ) Settlement (35.0 ) — December 31 548.6 521.2
Schedule of assumptions used to determine defined benefit obligations	The weighted average assumptions used to determine defined benefit obligations at December 31 , 2017 , and 2016 are as follows: Retirement Plans 2017 2016 Discount rate 2.47 % 2.64 % Expected rate of salary increases 3.26 % 3.26 % Future pension trend rate increases 2.97 % 2.98 %
Changes in the fair value of plan assets	Changes in the fair value of plan assets in the current period were as follows: Retirement Plans $ in millions 2017 2016 January 1 424.1 422.7 Actual return on plan assets 52.3 71.0 Exchange difference 41.9 (69.9 ) Contributions from the company 11.8 14.2 Benefits paid (9.0 ) (13.9 ) Settlement and other (34.2 ) — December 31 486.9 424.1
Breakdown of amount recognized in accumulated other comprehensive income	The components of the amount recognized in accumulated other comprehensive income at December 31 , 2017 , and 2016 are as follows: Retirement Plans $ in millions 2017 2016 Prior service cost/(credit) 3.9 3.7 Net actuarial loss/(gain) 128.3 164.1 Total 132.2 167.8
Breakdown of amounts in accumulated other comprehensive income expected to be amortized into net periodic benefit cost	The amounts in accumulated other comprehensive income expected to be amortized into the Consolidated Income Statement during the year ending December 31 , 2018 are as follows: $ in millions Retirement Plans Prior service cost/(credit) 0.1 Net actuarial loss/(gain) 2.4 Total 2.5
Schedule of benefit obligations in excess of plan assets	The total accumulated benefit obligation and fair value of plan assets for plans with accumulated benefit obligations in excess of plan assets and the projected benefit obligation and fair value of plan assets for pension plans with projected benefit obligations in excess of plan assets are as follows: Retirement Plans $ in millions 2017 2016 Plans with accumulated benefit obligation in excess of plan assets: Accumulated benefit obligation 539.4 512.1 Fair value of plan assets 474.1 411.6 Plans with projected benefit obligation in excess of plan assets: Projected benefit obligation 539.4 512.1 Fair value of plan assets 474.1 411.6
Schedule of defined benefit plans	The components of net periodic benefit cost in respect of these defined benefit plans are as follows: Retirement Plans Medical Plan $ in millions 2017 2016 2015 2016 2015 Service cost 2.3 4.6 5.4 — — Interest cost 14.1 16.5 17.7 — — Expected return on plan assets (22.6 ) (21.7 ) (22.9 ) — — Amortization of prior service cost/(credit) 0.2 — 0.1 (11.3 ) (11.3 ) Amortization of net actuarial (gain)/loss 3.0 1.8 3.0 (0.3 ) (0.3 ) Settlement 7.3 — — (9.0 ) — Net periodic benefit cost/(credit) 4.3 1.2 3.3 (20.6 ) (11.6 )
Schedule of assumptions used to determine net periodic benefit cost	The weighted average assumptions used to determine net periodic benefit cost for the years ended December 31 , 2017 , 2016 , and 2015 are: Retirement Plans 2017 2016 2015 Discount rate 2.64 % 3.69 % 3.52 % Expected return on plan assets 5.01 % 5.53 % 5.90 % Expected rate of salary increases 3.26 % 3.16 % 3.06 % Future pension rate increases 2.98 % 2.98 % 2.88 %
Analysis of plan assets	The analysis of the plan assets as of December 31, 2017 was as follows: $ in millions Retirement Plans % of Plan Assets Cash and cash equivalents 10.7 2.2 % Fund investments 227.9 46.8 % Equity securities 133.9 27.5 % Government debt securities 20.9 4.3 % Other assets 13.4 2.8 % Guaranteed investments contracts 80.1 16.5 % Total 486.9 100.0 % The analysis of the plan assets as of December 31, 2016 was as follows: $ in millions Retirement Plans % of Plan Assets Cash and cash equivalents 3.9 0.9 % Fund investments 207.4 48.9 % Equity securities 122.1 28.8 % Government debt securities 73.0 17.2 % Other assets 7.3 1.7 % Guaranteed investments contracts 10.4 2.5 % Total 424.1 100.0 %
Schedule of fair value of plan assets by three level fair value hierarchy	The following table presents the carrying value of the plan assets, including major security type for equity and debt securities, which are measured at fair value as of December 31, 2017 : As of December 31, 2017 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and cash equivalents 10.7 10.7 — — Fund investments 227.9 227.9 — — Equity securities 133.9 133.9 — — Government debt securities 20.9 13.9 7.0 — Other assets 80.1 80.1 — — Guaranteed investments contracts 13.4 — — 13.4 Total 486.9 466.5 7.0 13.4 The following table presents the carrying value of the plan assets, including major security type for equity and debt securities, which are measured at fair value as of December 31, 2016 : As of December 31, 2016 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and cash equivalents 3.9 3.9 — — Fund investments 207.4 207.4 — — Equity securities 122.1 122.1 — — Government debt securities 73.0 13.7 59.3 — Other assets 7.3 7.3 — — Guaranteed investment contracts 10.4 — — 10.4 Total 424.1 354.4 59.3 10.4
Schedule of benefits expected to be paid in next five fiscal years and the five fiscal years thereafter	The benefits expected to be paid in each of the next five fiscal years and in the five fiscal years thereafter are as follows: $ in millions Retirement Plans Expected benefit payments: 2018 9.3 2019 9.6 2020 10.0 2021 10.3 2022 10.6 Thereafter in the succeeding five years 59.3

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Schedule Of Future Commitments Under Non Cancelable Operating Leases	As of December 31, 2017 , the company's total future commitments by year under non-cancelable operating leases are as follows: $ in millions Total Buildings Other 2018 59.7 57.6 2.1 2019 61.6 59.6 2.0 2020 53.6 51.6 2.0 2021 50.7 49.8 0.9 2022 48.5 48.5 — Thereafter 90.4 90.4 — Gross lease commitments 364.5 357.5 7.0 Less: future minimum payments expected to be received under non-cancelable subleases 6.7 6.7 — Net lease commitments 357.8 350.8 7.0

Other Gains and Losses, Net (Ta

Other Gains and Losses, Net (Tables)	12 Months Ended
	Dec. 31, 2017
OTHER GAINS AND LOSSES, NET
Schedule of other gains and losses, net	The components of other gains and losses, net, are as follows: $ in millions 2017 2016 2015 Other gains: Gain on sale of investments 11.3 1.5 3.8 Gain on trading investments, net 40.4 14.2 — Foreign exchange hedge gain — 22.0 — Gain on contingent consideration liability 7.6 — 27.1 Net foreign exchange gains 16.2 — — Other realized gains 0.2 1.4 0.9 Total other gains 75.7 39.1 31.8 Other losses: Other-than-temporary impairment of available-for-sale investments (3.2 ) — (2.0 ) Loss on trading investments, net — — (13.5 ) Loss on contingent consideration liability — (7.4 ) — Net foreign exchange losses — (6.0 ) (2.4 ) Foreign exchange hedge loss (21.0 ) — (7.7 ) Realized loss on sale of partnerships — — (7.3 ) Other realized losses — (2.8 ) (0.4 ) Total other losses (24.2 ) (16.2 ) (33.3 ) Other gains and losses, net 51.5 22.9 (1.5 )

Taxation (Tables)

Taxation (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Summary of (provision) benefit for income taxes	The company's (provision) for income taxes for the years ended December 31 , 2017 , 2016 and 2015 is summarized as follows: $ in millions 2017 2016 2015 Current: Federal (147.5 ) (161.0 ) (221.0 ) State (30.2 ) (18.9 ) (23.4 ) Foreign (142.2 ) (143.0 ) (161.4 ) (319.9 ) (322.9 ) (405.8 ) Deferred: Federal 63.0 (21.1 ) 11.9 State (11.2 ) (0.9 ) (5.2 ) Foreign (0.1 ) 6.6 1.1 51.7 (15.4 ) 7.8 Total income tax (provision) (268.2 ) (338.3 ) (398.0 )
Schedule of deferred tax recognized on balance sheet	The net deferred tax recognized in the Consolidated Balance Sheets at December 31 , 2017 and 2016 , respectively, includes the following: $ in millions 2017 2016 Deferred tax assets: Deferred compensation arrangements 57.6 79.1 Accrued rent expenses 7.2 12.3 Tax loss carryforwards 94.6 64.8 Postretirement medical, pension and other benefits 16.6 24.4 Investment basis differences 32.8 58.3 Accrued bonus 8.8 64.8 Other 17.2 24.5 Total deferred tax assets 234.8 328.2 Valuation allowance (94.7 ) (59.0 ) Deferred tax assets, net of valuation allowance 140.1 269.2 Deferred tax liabilities: Deferred sales commissions (11.0 ) (13.5 ) Goodwill and intangibles (377.3 ) (509.6 ) Fixed assets (19.2 ) (27.6 ) Other (8.8 ) (9.2 ) Total deferred tax liabilities (416.3 ) (559.9 ) Net deferred tax assets/(liabilities) (276.2 ) (290.7 )
Reconciliation between statutory and effective tax rates on income from operations	A reconciliation between the statutory rate and the effective tax rate on income from operations for the years ended December 31 , 2017 , 2016 and 2015 is as follows: 2017 2016 2015 Statutory Rate 35.0 % 35.0 % 35.0 % Foreign jurisdiction statutory income tax rates (9.6 )% (8.1 )% (9.2 )% State taxes, net of federal tax effect 2.2 % 1.6 % 1.6 % Impact of the 2017 Tax Act (9.3 )% — % — % Change in valuation allowance for unrecognized tax losses 0.4 % (0.4 )% (0.1 )% Share Based Compensation (0.3 )% — % — % Other 1.2 % 0.3 % 1.8 % (Gains)/losses attributable to noncontrolling interests (0.8 )% (0.4 )% 0.1 % Effective tax rate per Consolidated Statements of Income 18.8 % 28.0 % 29.2 %
Division of income/(losses) before taxes between U.S. and foreign	The enacted U.K. statutory tax rate, for U.S. GAAP purposes, was 19% as of December 31, 2017 . As of December 31, 2017 , the U.S. federal statutory tax rate was 35% . The 2017 Tax Act enacted for U.S. GAAP purposes on December 22, 2017 reduces the U.S. federal statutory tax rate to 21% from January 1, 2018.
Reconciliation Of Changes In Unrecognized Tax Benefits	A reconciliation of the change in the UTB balance from January 1, 2015 , to December 31, 2017 , is as follows: $ in millions Gross Unrecognized Income Tax Benefits Balance at January 1, 2015 6.0 Additions for tax positions related to the current year 2.5 Additions for tax positions related to prior years 2.2 Other reductions for tax positions related to prior years (1.1 ) Reductions for statute closings — Balance at December 31, 2015 9.6 Additions for tax positions related to the current year 0.9 Additions for tax positions related to prior years 0.1 Other reductions for tax positions related to prior years (0.1 ) Reductions for statute closings — Balance at December 31, 2016 10.5 Additions for tax positions related to the current year 0.9 Additions for tax positions related to prior years 11.5 Other reductions for tax positions related to prior years (0.2 ) Reductions for statute closings (3.1 ) Balance at December 31, 2017 19.6

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Calculation Of Earnings Per Share	The calculation of earnings per share is as follows: Years ended December 31, In millions, except per share data 2017 2016 2015 Net income, net of taxes $1,161.0 $868.3 $964.1 Net (income)/loss attributable to noncontrolling interests in consolidated entities (33.7 ) (14.1 ) 4.0 Net income attributable to Invesco Ltd. for basic and diluted EPS calculations 1,127.3 854.2 968.1 Less: Allocation of earnings to restricted shares (33.7 ) (24.8 ) (24.6 ) Net income attributable to common shareholders $1,093.6 $829.4 $943.5 Invesco Ltd: Weighted average shares outstanding - basic 409.4 414.7 428.9 Dilutive effect of non-participating share-based awards 0.5 0.3 0.4 Weighted average shares outstanding - diluted 409.9 415.0 429.3 Common shareholders: Weighted average shares outstanding - basic 409.4 414.7 428.9 Less: Weighted average restricted shares (12.2 ) (12.1 ) (10.9 ) Weighted average common shares outstanding- basic 397.2 402.6 418.0 Dilutive effect of non-participating share-based awards 0.5 0.3 0.4 Weighted average common shares outstanding - diluted 397.7 402.9 418.4 Earnings per share: Basic earnings per share $2.75 $2.06 $2.26 Diluted earnings per share $2.75 $2.06 $2.26

Geographic Information (Tables)

Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segments, Geographical Areas [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	The company operates under one business segment, investment management. Geographical information is presented below. There are no revenues or long-lived assets attributed to the company's country of domicile, Bermuda. $ in millions U.S. U.K. Continental Europe/Ireland Canada Asia Total For the year ended December 31, 2017 Revenue from external customers 2,747.9 955.8 999.6 339.0 118.0 5,160.3 Inter-company revenue (5.6 ) 122.8 (243.0 ) (16.9 ) 142.7 — Total operating revenues 2,742.3 1,078.6 756.6 322.1 260.7 5,160.3 Long-lived assets 332.2 118.3 10.0 8.9 21.3 490.7 For the year ended December 31, 2016 Revenue from external customers 2,544.2 930.9 826.8 325.5 107.0 4,734.4 Inter-company revenue (27.0 ) 99.0 (188.9 ) (10.3 ) 127.2 — Total operating revenues 2,517.2 1,029.9 637.9 315.2 234.2 4,734.4 Long-lived assets 331.6 95.9 10.7 9.4 17.1 464.7 For the year ended December 31, 2015 Revenue from external customers 2,622.1 1,153.0 891.9 353.9 102.0 5,122.9 Inter-company revenue (8.6 ) 114.4 (216.7 ) (7.0 ) 117.9 — Total operating revenues 2,613.5 1,267.4 675.2 346.9 219.9 5,122.9 Long-lived assets 306.7 88.3 6.8 10.0 15.1 426.9

Consolidated Investment Produ47

Consolidated Investment Products (Tables)	12 Months Ended
	Dec. 31, 2017
Consolidated Investment Products [Abstract]
Balances Related To CIP	The following table presents the balances related to CIP that are included on the Consolidated Balance Sheets as well as Invesco's net interest in the CIP for each period presented. At December 31, 2017 all CIP are VIEs. As of $ in millions December 31, 2017 December 31, 2016 Cash and cash equivalents of CIP 511.3 742.2 Accounts receivable and other assets of CIP 131.5 106.2 Investments of CIP 5,658.0 5,116.1 Less: Debt of CIP (4,799.8 ) (4,403.1 ) Less: Other liabilities of CIP (498.8 ) (673.4 ) Less: Retained earnings 16.7 19.0 Less: Accumulated other comprehensive income, net of tax (16.6 ) (18.0 ) Less: Equity attributable to redeemable noncontrolling interests (243.2 ) (283.7 ) Less: Equity attributable to nonredeemable noncontrolling interests (258.6 ) (107.2 ) Invesco's net interests in CIP 500.5 498.1
Condensed Consolidating Statement Of Income Line Items Reflecting Impact Of Consolidation Of Investment Products Into The Condensed Consolidated Statements Of Income	The following table reflects the impact of consolidation of investment products into the Consolidated Statements of Income for the years ended December 31 , 2017 , 2016 and 2015 . Summary of Income Statement Impact of CIP Years ended December 31, $ in millions 2017 2016 2015 Total operating revenues (32.4 ) (22.3 ) (39.2 ) Total operating expenses 10.5 28.7 24.0 Operating income (42.9 ) (51.0 ) (63.2 ) Equity in earnings of unconsolidated affiliates (20.0 ) (8.9 ) (1.7 ) Interest and dividend income — (0.3 ) (4.4 ) Other gains and losses, net (38.4 ) (1.9 ) (3.9 ) Interest and dividend income of CIP 211.6 195.3 253.0 Interest expense of CIP (155.3 ) (123.5 ) (188.9 ) Other gains/(losses) of CIP, net 81.0 7.4 (37.0 ) Income before income taxes 36.0 17.1 (46.1 ) Income tax provision — — — Net income 36.0 17.1 (46.1 ) Net (income)/loss attributable to noncontrolling interests in consolidated entities (33.7 ) (14.1 ) 5.7 Net income attributable to Invesco Ltd. 2.3 3.0 (40.4 )
Schedule of Variable Interest Entities [Table Text Block]	At December 31, 2017 , the company's carrying value and maximum risk of loss with respect to VIEs in which the company is not the primary beneficiary was $227.3 million ( December 31, 2016 : $234.4 million ).
VIE Balance Sheets Consolidated In Period	For the year ended December 31, 2017 For the year ended December 31, 2016 $ in millions VIEs VIEs VOEs Cash and cash equivalents of CIP 277.8 609.8 — Accounts receivable and other assets of CIP 11.5 108.5 0.2 Investments of CIP 851.8 1,032.8 49.8 Total assets 1,141.1 1,751.1 50.0 Debt of CIP 544.2 1,013.3 — Other liabilities of CIP 331.5 472.4 — Total liabilities 875.7 1,485.7 — Total equity 265.4 265.4 50.0 Total liabilities and equity 1,141.1 1,751.1 50.0 During the year ended December 31, 2017 , the company determined it was no longer the primary beneficiary of eight VIEs and one VOE. During the year ended December 31, 2016 , the company determined that it was no longer the primary beneficiary of ten VIEs. The amounts deconsolidated from the Consolidated Balance Sheets are illustrated in the table below. There was no net impact to the Consolidated Statements of Income for the years ended December 31, 2017 and December 31, 2016 from the deconsolidation of these investment products. For the year ended December 31, 2017 For the year ended December 31, 2016 $ in millions VIEs VOEs VIEs Cash and cash equivalents of CIP 15.8 — 40.1 Accounts receivable and other assets of CIP 4.1 0.2 19.0 Investments of CIP 358.1 49.8 418.0 Total assets 378.0 50.0 477.1 Debt of CIP 4.2 — — Other liabilities of CIP 3.1 — 23.9 Total liabilities 7.3 — 23.9 Total equity 370.7 50.0 453.2 Total liabilities and equity 378.0 50.0 477.1
Fair Value Hierarchy Levels Of Investments Held And Notes Issued By Consolidated Investment Products	December 31, 2017 and December 31, 2016 : As of December 31, 2017 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV as a practical expedient Assets: Bank loans 4,894.2 — 4,894.2 — — Bonds 302.0 — 302.0 — — Equity securities 203.2 198.8 4.4 — — Equity and fixed income mutual funds 19.0 19.0 — — — Investments in other private equity funds 163.4 — — — 163.4 Real estate investments 76.2 — — 76.2 — Total assets at fair value 5,658.0 217.8 5,200.6 76.2 163.4 As of December 31, 2016 $ in millions Fair Value Measurements Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV as a Practical expedient Assets: Bank loans 4,397.8 — 4,397.8 — — Bonds 370.9 — 370.9 — — Equity securities 167.4 166.0 1.4 — — Equity and fixed income mutual funds 13.0 13.0 — — — Investments in other private equity funds 68.6 — — — 68.6 Real estate investments 40.7 — — 40.7 — Investments in fixed income fund of funds 57.7 — — — 57.7 Total assets at fair value 5,116.1 179.0 4,770.1 40.7 126.3
Beginning And Ending Fair Value Measurements For Level 3 Assets And Liabilities	The following table shows a reconciliation of the beginning and ending fair value measurements for level 3 assets and liabilities using significant unobservable inputs: Year ended December 31, 2017 Year ended December 31, 2016 $ in millions Level 3 Assets Level 3 Assets Beginning balance 40.7 388.6 Adjustment for adoption of ASU 2015-02 — (388.6 ) Purchases 15.1 39.4 Sales (4.5 ) — Gains and losses included in the Consolidated Statements of Income* 24.9 1.3 Ending balance 76.2 40.7 ____________ * Included in gains/(losses) of CIP, net in the Consolidated Statement of Income for the year ended December 31, 2017 are $24.5 million in net unrealized gains attributable to investments still held at December 31, 2017 by CIP (year ended December 31, 2016 : $1.3 million net unrealized gains attributable to investments still held at December 31, 2016 ).
Fair Value Inputs, Assets and Liabilities, Quantitative Information, Consolidated Investment Products	The following table shows significant unobservable inputs used in the fair value measurement of level 3 assets at December 31, 2017 : Assets and Liabilities * Fair Value at December 31, 2017 ($ in millions) Valuation Technique Unobservable Inputs Range Weighted Average (by fair value) Real Estate Investments $76.2 Discounted Cash Flow Discount rate 7% - 33% 17.0 % Terminal capitalization rate 5.3% 5.3 % Average rent growth rate 2%-3% 2.5 % At December 31, 2016 , $40.7 million of investments held by consolidated real estate funds were valued using recent private market transactions. The following narrative will indicate the sensitivity of inputs illustrating the impact of significant increases to the inputs. A directionally opposite impact would apply for significant decreases in these inputs: • For real estate investments, a change in the average rent growth rate would result in a directionally-opposite change in the assumptions for discount rate and terminal capitalization rate. Significant increases in the average growth rate would result in significantly higher fair values. Significant increases in the assumptions for discount rate and terminal capitalization rate in isolation would result in significantly lower fair value measurements. The table below summarizes as of December 31, 2017 and December 31, 2016 , the nature of investments that are valued using the NAV as a practical expedient and any related liquidation restrictions or other factors which may impact the ultimate value realized: December 31, 2017 December 31, 2016 in millions, except term data Fair Value Total Unfunded Commitments Weighted Average Remaining Term (2) Fair Value Total Unfunded Commitments Weighted Average Remaining Term (2) Private equity funds (1) $163.4 $53.9 5.5 years $68.6 $41.9 7.0 years Investments in fixed income fund of funds (3) — — n/a 57.7 — n/a ____________ (1) These investments are not subject to redemption; however, for certain funds, the investors may sell or transfer their interest, which may require approval by the general partner of the underlying funds. (2) These investments are expected to be returned through distributions as a result of liquidations of the funds' underlying assets over the weighted average periods indicated.

Related Parties (Tables)

Related Parties (Tables)	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	Years ended December 31, $ in millions 2017 2016 2015 Affiliated operating revenues: Investment management fees 3,624.7 3,274.3 3,565.8 Service and distribution fees 851.2 822.3 854.0 Performance fees 73.8 21.5 29.2 Other 59.1 79.8 108.5 Total affiliated operating revenues 4,608.8 4,197.9 4,557.5 As of December 31, $ in millions 2017 2016 Affiliated asset balances: Cash and cash equivalents 875.5 476.2 Unsettled fund receivables 204.0 253.2 Accounts receivable 359.9 344.4 Investments 608.5 728.3 Assets held for policyholders 12,444.2 8,224.2 Other assets 9.2 2.9 Total affiliated asset balances 14,501.3 10,029.2 Affiliated liability balances: Accrued compensation and benefits 90.7 76.5 Accounts payable and accrued expenses 64.5 94.7 Unsettled fund payables 288.8 318.7 Total affiliated liability balances 444.0 489.9

Accounting Policies (Narrative)

Accounting Policies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)reporting_units	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Line Items]
Available-for-sale Securities	$ 85.2	$ 154
Liabilities and Equity	$ 31,668.8	25,734.3
Fair value of recognized acquired assets	100.00%
Non controlling interest in acquisitions	100.00%
Recognized liabilities acquired	100.00%
Cash deposits with clearing organizations	$ 11.4	11.4
Reporting Units for Goodwill | reporting_units	1
Net Waivers	$ 1.4
Share Based Payment, Estimated Forfeitures, Percentage	3.00%
Percentage of Excess in Projected Benefit Obligation and Fair Value Assets To Be Amortized	10.00%
Advertising Costs	$ 37.2	32.7	$ 35.4
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation		1.7	21.2
Payments Related to Tax Withholding for Share-based Compensation	63.8	42	74.9
Change in cash held at consolidated investment products	$ (226.2)	509.4	$ (39.9)
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	50 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	3 years
Intangible assets, useful life, years	2 years
Minimum [Member] | CLO [Member]
Property, Plant and Equipment [Line Items]
Reporting Period Lag Between Parent Company and Consolidated Entity	1 month
Minimum [Member] | Software Development [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	5 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Cash Equivalent, Maturity Period	3 months
Settlement Period for Fund and Investor Receivables	4 days
Amortization Period of Sales Commission of Share B Redemptions	6 years
Property, Plant and Equipment, Useful Life, Minimum	7 years
Intangible assets, useful life, years	12 years
Maximum [Member] | CLO [Member]
Property, Plant and Equipment [Line Items]
Reporting Period Lag Between Parent Company and Consolidated Entity	3 months
Maximum [Member] | Software Development [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	7 years
Waiver [Member]
Property, Plant and Equipment [Line Items]
Investment Advisory, Management and Administrative Fees	$ 4.7
Change in Third party distribution service and advisory fee	70.00%
Accounting Standards Update 2015-02 [Member]
Property, Plant and Equipment [Line Items]
Liabilities and Equity		3,170.6
Accounting Standards Update 2015-02 [Member] | Consolidation, Eliminations [Member]
Property, Plant and Equipment [Line Items]
Liabilities and Equity		458.5
Accounting Standards Update 2016-09
Property, Plant and Equipment [Line Items]
Excess Tax Benefit from Share-based Compensation, Operating Activities	$ 3.8
CLO [Member] | Accounting Standards Update 2015-02 [Member]
Property, Plant and Equipment [Line Items]
Liabilities and Equity		2,366.5
Seed Money [Member]
Property, Plant and Equipment [Line Items]
Available-for-sale Securities	69.3	127.9
Seed Money [Member]
Property, Plant and Equipment [Line Items]
Available-for-sale Securities	69.3	$ 127.9
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	$ 4.2

Fair Value Of Assets And Liab50

Fair Value Of Assets And Liabilities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Gain (Loss) on Derivative, Net		$ (21)	$ 22
Indefinite-lived Intangible Assets Acquired		$ 167.1	63.4
Fair Value Inputs, Discount Rate		3.89%
Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-lived Intangible Assets Acquired	$ 0		0
Designated as Hedging Instrument [Member] | Foreign Exchange Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Put option contracts, purchases		$ 8.1	$ 14.5
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets under Management, Assumed Growth Rate		(9.20%)
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets under Management, Assumed Growth Rate		8.35%
Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets under Management, Assumed Growth Rate		0.16%
Total Return Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Gain (Loss) on Derivative, Net		$ 8.8
Notional value of futures contracts		108.3
Fair Value, Inputs, Level 2 [Member] | Total Return Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		$ 1.6

Fair Value Of Assets And Liab51

Fair Value Of Assets And Liabilities (Fair Value Of Financial Instruments Held By Consolidated Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 2,006.4	$ 1,328	$ 1,851.4	$ 1,514.2
Available for sale investments	85.2	154
Foreign time deposits	28.6	26.9
Assets held for policyholders	12,444.5	8,224.2
Policyholder payables	(12,444.5)	(8,224.2)
Put option contracts	0.8	21.8
Assets, Fair Value Disclosure	13,683.3	9,205.8
Long-term debt	(2,075.8)	(2,102.4)
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2,006.4	1,328
Available for sale investments	85.2	154
Trading investments	277.3	329.6
Foreign time deposits	28.6	26.9
Assets held for policyholders	12,444.5	8,224.2
Policyholder payables	(12,444.5)	(8,224.2)
Put option contracts	0.8	21.8
UIT-related financial instruments sold, not yet purchased	(1.4)	(6)
Contingent consideration liability	(57.4)	(78.2)
Long-term debt	(2,075.8)	(2,102.4)
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2,006.4	1,328
Available for sale investments	85.2	154
Trading investments	277.3	329.6
Foreign time deposits	28.6	26.9
Assets held for policyholders	12,444.5	8,224.2
Policyholder payables	(12,444.5)	(8,224.2)
Put option contracts	0.8	21.8
UIT-related financial instruments sold, not yet purchased	(1.4)	(6)
Contingent consideration liability	(57.4)	(78.2)
Long-term debt	$ (2,258.1)	$ (2,206.5)

Fair Value Of Assets And Liab52

Fair Value Of Assets And Liabilities (Tri-Level Hierarchy, Carrying Value) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	$ 85.2	$ 154
Assets held for policyholders	12,444.5	8,224.2
Put option contracts	0.8	21.8
Total	(58.8)	(84.2)
Foreign time deposits	28.6	26.9
Equity method investments	277.3	279
Cost method investments	6.2	5.8
Assets, Fair Value Disclosure	13,683.3	9,205.8
Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased	(1.4)	(5.2)
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased		(0.8)
Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	(57.4)	(78.2)
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	875.5	476.2
Seed Money [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	69.3	127.9
Trading investments	173.7	121.9
Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	6	12.9
Other Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	9.9	13.2
Deferred Compensation Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	92.3	170.5
Common Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	8.9	30.4
Corporate Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	2	1.2
UIT-Related Equity And Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0.4	5.6
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for policyholders	12,444.5	8,224.2
Put option contracts	0	0
Total	(1.4)	(6)
Assets, Fair Value Disclosure	13,666.6	9,157.9
Fair Value, Inputs, Level 1 [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased	(1.4)	(5.2)
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased		(0.8)
Fair Value, Inputs, Level 1 [Member] | Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	0	0
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	875.5	476.2
Fair Value, Inputs, Level 1 [Member] | Seed Money [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	69.3	127.9
Trading investments	173.7	121.9
Fair Value, Inputs, Level 1 [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0	0
Fair Value, Inputs, Level 1 [Member] | Other Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0	0
Fair Value, Inputs, Level 1 [Member] | Deferred Compensation Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	92.3	170.5
Fair Value, Inputs, Level 1 [Member] | Common Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	8.9	30.4
Fair Value, Inputs, Level 1 [Member] | Corporate Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	2	1.2
Fair Value, Inputs, Level 1 [Member] | UIT-Related Equity And Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0.4	5.6
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for policyholders	0	0
Put option contracts	0.8	21.8
Total	0	0
Assets, Fair Value Disclosure	6.8	21.8
Fair Value, Inputs, Level 2 [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased	0	0
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased		0
Fair Value, Inputs, Level 2 [Member] | Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	0	0
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | Seed Money [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0	0
Trading investments	0	0
Fair Value, Inputs, Level 2 [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	6	0
Fair Value, Inputs, Level 2 [Member] | Other Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0	0
Fair Value, Inputs, Level 2 [Member] | Deferred Compensation Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 2 [Member] | Common Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 2 [Member] | Corporate Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 2 [Member] | UIT-Related Equity And Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for policyholders	0	0
Put option contracts	0	0
Total	(57.4)	(78.2)
Assets, Fair Value Disclosure	9.9	26.1
Fair Value, Inputs, Level 3 [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased	0	0
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
UIT-related financial instruments sold, not yet purchased		0
Fair Value, Inputs, Level 3 [Member] | Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	(57.4)	(78.2)
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Seed Money [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0	0
Trading investments	0	0
Fair Value, Inputs, Level 3 [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0	12.9
Fair Value, Inputs, Level 3 [Member] | Other Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	9.9	13.2
Fair Value, Inputs, Level 3 [Member] | Deferred Compensation Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 3 [Member] | Common Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 3 [Member] | Corporate Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	0
Fair Value, Inputs, Level 3 [Member] | UIT-Related Equity And Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading investments	0	$ 0
Total Return Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	$ 1.6

Fair Value Of Assets And Liab53

Fair Value Of Assets And Liabilities (Reconciliation Of Balance, Fair Value Measurement, Level 3) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance, as adjusted			$ 7,962.2	$ 9,102.2
Indefinite-lived Intangible Assets Acquired		$ (167.1)	(63.4)
Accounting Standards Update 2015-02 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				(733.5)
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance (Asset)	$ 40.7	40.7	388.6
Purchases		(15.1)	(39.4)
Gains and losses included in the Consolidated Statements of Income		(24.9)	(1.3)
Ending balance (Asset)		76.2	40.7	388.6
Liability [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Indefinite-lived Intangible Assets Acquired	0		0
Liability [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance (Liability)	(78.2)	(78.2)	(83.9)
Beginning Balance, as adjusted	78.2	78.2	83.9
Returns of capital		0	0
Net unrealized gains and losses included in other gains and losses		7.6	(7.4)
Net unrealized gains and losses included in accumulated other comprehensive income/ (loss) Liability		0	0
Settlements (Liability)		13.2	13.1
Ending balance (Liability)		(57.4)	(78.2)	(83.9)
Liability [Member] | Fair Value, Inputs, Level 3 [Member] | Accounting Standards Update 2015-02 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			0	0
Liability [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases				119.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3		0	0
Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases		0	0
Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance (Asset)	12.9	12.9	1.4
Beginning Balance, as adjusted	12.9	12.9	12.9
Returns of capital		0	(3)
Gains and losses included in the Consolidated Statements of Income		0	0
Net unrealized gains and losses included in accumulated other comprehensive income/(loss)		0	3
Settlements (Asset)		0	0
Ending balance (Asset)		0	12.9	1.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(12.9)	0
Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Accounting Standards Update 2015-02 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			0	11.5
Other Debt Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases		(7.4)	(21.4)
Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance (Asset)	13.2	13.2	5.9
Beginning Balance, as adjusted	$ 13.2	13.2	5.9
Returns of capital		0	0
Gains and losses included in the Consolidated Statements of Income		(3.2)	0
Net unrealized gains and losses included in accumulated other comprehensive income/(loss)		0	0
Settlements (Asset)		(7.5)	(14.1)
Ending balance (Asset)		9.9	13.2	5.9
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0	0
Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Accounting Standards Update 2015-02 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ 0	$ 0
Total Return Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative Asset		$ 1.6

Investments (Narrative) (Detail

Investments (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)fund	Dec. 31, 2016USD ($)fund	Dec. 31, 2015USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	$ 7,200,000	$ (600,000)	$ 2,500,000
Number of affiliated funds holding seed money | fund	50	103
Gains and losses on trading securities	$ 18,900,000	$ 16,900,000
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage Ownership In Private Equity, Real Estate, and Other Entities	5.00%
Seed Money [Member]
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairment charges on seed money investments	$ (3,200,000)	$ 0

Investments (Details Of Company

Investments (Details Of Company Investments, Current) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Investment Holdings [Line Items]
Available for sale investments	$ 85.2	$ 154
Equity method investments	277.3	279
Foreign time deposits	28.6	26.9
Cost Method Investments	6.2	5.8
Investments	674.6	795.3
Seed Money [Member]
Investment Holdings [Line Items]
Available for sale investments	69.3	127.9
Trading investments	173.7	121.9
Collateralized Loan Obligations [Member]
Investment Holdings [Line Items]
Available for sale investments	6	12.9
Other Debt Obligations [Member]
Investment Holdings [Line Items]
Available for sale investments	9.9	13.2
Deferred Compensation Arrangements [Member]
Investment Holdings [Line Items]
Trading investments	92.3	170.5
UIT-Related Equity And Debt Securities [Member]
Investment Holdings [Line Items]
Trading investments	2.4	6.8
Common Shares [Member]
Investment Holdings [Line Items]
Trading investments	$ 8.9	$ 30.4

Investments (Realized Gains Los

Investments (Realized Gains Losses Available-For-Sale Securities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Sale of available-for-sale investments	$ 79.5	$ 59.3	$ 51.1
Gross Realized Gains	8.7	1.5	2.7
Gross Realized Losses	(1.5)	(2.1)	(0.2)
Seed Money [Member]
Schedule of Available-for-sale Securities [Line Items]
Sale of available-for-sale investments	62.5	42.7	48.1
Gross Realized Gains	4.3	1.5	2.2
Gross Realized Losses	(1.5)	(1.6)	(0.2)
Collateralized Loan Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Sale of available-for-sale investments	7.1	3	2.6
Gross Realized Gains	1.9	0	0.5
Gross Realized Losses	0	0	0
Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Sale of available-for-sale investments	9.9	13.6	0.4
Gross Realized Gains	2.5	0	0
Gross Realized Losses	$ 0	$ (0.5)	$ 0

Investments (Gross Unrealized H

Investments (Gross Unrealized Holding Gains And Losses Recognized In Other Accumulated Comprehensive Income From Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 79.9	$ 149.6
Gross Unrealized Holding Gains	6.6	10.5
Gross Unrealized Holding Losses	(1.3)	(6.1)
Available for sale investments	85.2	154
Seed Money [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	65.1	127.2
Gross Unrealized Holding Gains	5.5	6.8
Gross Unrealized Holding Losses	(1.3)	(6.1)
Available for sale investments	69.3	127.9
CLO [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	4.9	9.2
Gross Unrealized Holding Gains	1.1	3.7
Gross Unrealized Holding Losses	0	0
Available for sale investments	6	12.9
Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	9.9	13.2
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Available for sale investments	$ 9.9	$ 13.2

Investments (Breakdown Of Avail

Investments (Breakdown Of Available-For-Sale Investments With Unrealized Losses) (Details) - Seed Money Funds [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 9.4	$ 1.9
Less than 12 Months, Gross Unrealized Losses	(0.8)	(0.2)
12 Months or Greater, Fair Value	15	56.4
12 Months or Greater, Gross Unrealized Losses	(0.5)	(5.9)
Total, Fair Value	24.4	58.3
Total, Gross Unrealized Losses	$ (1.3)	$ (6.1)

Investments Held-to-maturity Se

Investments Held-to-maturity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities	$ 85.2	$ 154
Available-for-sale Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	9.9
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	2.8
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	3.2
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	0
Available-for-sale Securities	$ 15.9

Investments (Summary of the Com

Investments (Summary of the Company's Investment in Joint Ventures and Affiliates) (Details)	Dec. 31, 2017
CHINA | Huaneng Invesco WLR Investment Consulting Company Limited [Member]
Equity Method Investment, Ownership Percentage	50.00%
CHINA | Invesco Great Wall Fund Management Company Limited [Member]
Equity Method Investment, Ownership Percentage	49.00%
POLAND | Pocztylion - ARKA [Member]
Equity Method Investment, Ownership Percentage	29.30%

Investments (Summary of the C61

Investments (Summary of the Companies Voting Control in Entities Where it has Noncontrolling Interest) (Details) - Germany	Dec. 31, 2017
VV Immobilien Verwaltungs und Beteiligungs Gmbh [Member]
Voting Interest Owned	70.00%
VV Immobilien Verwaltungs GmbH [Member]
Voting Interest Owned	70.00%
HVH Immobilien und Beteiligungs GmbH [Member]
Voting Interest Owned	70.00%

Property, Equipment And Softw62

Property, Equipment And Software (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Equipment and Software, Gross	$ 1,219.6	$ 1,105.8
Less: Accumulated Depreciation	(728.9)	(641.1)
Property, Equipment and Software, Net	490.7	464.7
Depreciation expense	99.4	87.3	$ 83
Technology Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Equipment and Software, Gross	261	242.3
Computer Software, Intangible Asset [Member]
Property, Plant and Equipment [Line Items]
Property, Equipment and Software, Gross	621.9	467.4
Land and Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, Equipment and Software, Gross	87.5	68.2
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Equipment and Software, Gross	204.4	210.9
Work in Process [Member]
Property, Plant and Equipment [Line Items]
Property, Equipment and Software, Gross	$ 44.8	$ 117

Intangible Assets (Narrative) (

Intangible Assets (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Indefinite-lived Intangible Assets Acquired	$ 167,100,000	$ 63,400,000
Amortization expense	17,400,000	13,900,000	$ 10,600,000
Gross Book Value	1,659,700,000	$ 1,481,100,000
Impaired Intangible Asset, Description	$ 0

Intangible Assets (Schedule of

Intangible Assets (Schedule of finite-lived intangible assets by major class) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Gross Book Value	$ 1,659.7	$ 1,481.1
Accumulated Amortization	(101)	(81.7)
Net Book Value	1,558.7	1,399.4
Management contracts
Gross Book Value	68.8	67.7
Accumulated Amortization	(66.3)	(56.6)
Net Book Value	2.5	11.1
Customer relationships [Member]
Gross Book Value	40	40
Accumulated Amortization	(25.3)	(21.9)
Net Book Value	14.7	18.1
Other [Member]
Gross Book Value	27.6	9.8
Accumulated Amortization	(9.4)	(3.2)
Net Book Value	18.2	6.6
Finite-lived Intangible Assets Acquired	$ 16.9	$ 9.8
Weighted Average Amortization Period (years)	1 year 11 months	1 year 1 month
Management contracts
Gross Book Value	$ 1,523.3	$ 1,363.6
Net Book Value	$ 1,523.3	$ 1,363.6

Intangible Assets (Schedule O65

Intangible Assets (Schedule Of future amortization expense of intangible assets) (Details) $ in Millions	Dec. 31, 2017USD ($)
Intangible Assets, Net (Excluding Goodwill) [Abstract]
2,018	$ 15.6
2,019	8.1
2,020	4.7
2,021	4.7
2,022	$ 2.3

Goodwill (Schedule of Goodwill)

Goodwill (Schedule of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Abstract]
Goodwill, Acquired During Period	$ 193.3	$ 135.7
Goodwill, Impairment Loss	0
Goodwill [Roll Forward]
Net Book Value, Beginning Balance	6,129.2	6,175.7
Foreign exchange and other	268.2	(182.2)
Net Book Value, Ending Balance	$ 6,590.7	$ 6,129.2

Other Liabilities (Details)

Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Compensation and benefits	$ 101.2	$ 92.8
Accrued bonus and deferred compensation	594.9	561.5
Accrued compensation and benefits	696.1	654.3
Accruals and other liabilities	302.3	280.6
Deferred Revenue	60.4	87.7
Obligations, Fair Value Disclosure	57.4	78.2
Accounts payable	320.1	274.3
Income taxes payable	155.5	91.6
Accounts payable and accrued expenses	$ 895.7	$ 812.4

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)	Aug. 07, 2015USD ($)
Line of Credit Facility [Line Items]
Letters of Credit, Renewable Term	1 year
Line of Credit [Member]
Line of Credit Facility [Line Items]
Unsecured debt, credit agreement		$ 1,500,000,000
Credit facility, amount outstanding	$ 0
Margin for LIBOR based loans, percentage	1.00%
Margin for base rate loans, percentage	0.00%
Line of credit facility commitment fee amount, percentage	0.125%
Covenant ratio debt EBITDA maximum numerator	3.25
Covenant ratio coverage maximum numerator	4
Line of Credit [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Credit facility interest rate, percentage	1.00%
Line of Credit [Member] | Federal Funds [Member]
Line of Credit Facility [Line Items]
Credit facility interest rate, percentage	0.50%
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 10,600,000

Long-Term Debt (Schedule Of Lon

Long-Term Debt (Schedule Of Long-Term Debt Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument, Issuer	The issuer of the senior notes is an indirect 100% owned finance subsidiary of Invesco Ltd. (the Parent), and the Parent fully and unconditionally guaranteed the securities
Long-term debt	$ 2,075.8	$ 2,102.4
Unsecured Debt [Member] | Due November 30, 2022 [Member]
Unsecured Senior Notes	$ 596.9
Debt instrument, interest rate, stated percentage	3.125%
Debt Instrument, Maturity Date	Nov. 30, 2022
Debt Instrument, Face Amount	$ 600
Unsecured Debt [Member] | Due January 30, 2024 [Member]
Unsecured Senior Notes	$ 594
Debt instrument, interest rate, stated percentage	4.00%
Debt Instrument, Maturity Date	Jan. 30, 2024
Debt Instrument, Face Amount	$ 600
Unsecured Debt [Member] | Due January 15, 2026 [Member]
Unsecured Senior Notes	$ 495.1
Debt instrument, interest rate, stated percentage	3.75%
Debt Instrument, Maturity Date	Jan. 15, 2026
Debt Instrument, Face Amount	$ 500
Unsecured Debt [Member] | Due November 30, 2043 [Member]
Unsecured Senior Notes	$ 389.8
Debt instrument, interest rate, stated percentage	5.375%
Debt Instrument, Maturity Date	Nov. 30, 2043
Debt Instrument, Face Amount	$ 400
Line of Credit [Member]
Floating rate credit facility expiring August 11, 2022	0
Carrying Value [Member]
Long-term debt	2,075.8	2,102.4
Carrying Value [Member] | Unsecured Debt [Member] | Due November 30, 2022 [Member]
Unsecured Senior Notes	596.9	596.3
Carrying Value [Member] | Unsecured Debt [Member] | Due January 30, 2024 [Member]
Unsecured Senior Notes	594	593.2
Carrying Value [Member] | Unsecured Debt [Member] | Due January 15, 2026 [Member]
Unsecured Senior Notes	495.1	494.5
Carrying Value [Member] | Unsecured Debt [Member] | Due November 30, 2043 [Member]
Unsecured Senior Notes	389.8	389.7
Carrying Value [Member] | Line of Credit [Member]
Floating rate credit facility expiring August 11, 2022	0	28.7
Fair Value [Member]
Long-term debt	2,258.1	2,206.5
Fair Value [Member] | Unsecured Debt [Member] | Due November 30, 2022 [Member]
Unsecured Senior Notes	608.8	604.7
Fair Value [Member] | Unsecured Debt [Member] | Due January 30, 2024 [Member]
Unsecured Senior Notes	634.7	625.3
Fair Value [Member] | Unsecured Debt [Member] | Due January 15, 2026 [Member]
Unsecured Senior Notes	515	506.4
Fair Value [Member] | Unsecured Debt [Member] | Due November 30, 2043 [Member]
Unsecured Senior Notes	499.6	441.4
Fair Value [Member] | Line of Credit [Member]
Floating rate credit facility expiring August 11, 2022	$ 0	$ 28.7

Long-Term Debt (Analysis Of Bor

Long-Term Debt (Analysis Of Borrowings By Maturity) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt
Long-term debt	$ 2,075.8	$ 2,102.4
Unsecured Debt [Member] | Due November 30, 2022 [Member]
Debt
Borrowings	596.9
Unsecured Debt [Member] | Due January 30, 2024 [Member]
Debt
Borrowings	594
Unsecured Debt [Member] | Due January 15, 2026 [Member]
Debt
Borrowings	495.1
Unsecured Debt [Member] | Due November 30, 2043 [Member]
Debt
Borrowings	389.8
Line of Credit [Member]
Debt Instrument [Line Items]
Floating rate credit facility expiring August 11, 2022	$ 0

Share Capital (Narrative) (Deta

Share Capital (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Shares repurchased		18.1
Cost of repurchased shares		$ 535
Shares withheld to meet employees' tax withholding obligations	1.9	1.5
Fair values of shares withheld	$ 63.8	$ 42
Share repurchase plan, remaining authorized amount	$ 1,643	$ 1,643
Treasury stock shares	92.4	95.9
Treasury shares held, as unvested restricted stock awards	9.1	9.3
Common shares market price (per share)	$ 36.54
Treasury shares market value	$ 3,400

Share Capital (Movements In Sha

Share Capital (Movements In Shares Issued And Outstanding) (Details) - shares shares in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Common shares issued	490.4	490.4	490.4
Less: Treasury shares for which dividend and voting rights do not apply	(83.3)	(86.6)	(72.9)
Common shares outstanding	407.1	403.8	417.5

Share Capital (Movements in Tre

Share Capital (Movements in Treasury Shares) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Beginning balance	95.9	81.3	69.4
Acquisition of common shares	1.9	19.6	17.4
Distribution of common shares	(5.2)	(4.7)	(5.2)
Common shares distributed to meet ESPP obligation	(0.2)	(0.3)	(0.1)
Common shares distributed to meet option exercises	0	0	(0.2)
Ending balance	92.4	95.9	81.3

Other Comprehensive Income_(L74

Other Comprehensive Income/(Loss) (Accumulated other comprehensive income) (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2017GBP (£)
Other comprehensive income/(loss), net of tax:
Currency translation differences on investments in foreign subsidiaries	$ 389.4	$ (314.1)	$ (493.9)
Currency translation differences on investments in foreign subsidiaries	(15.3)
Actuarial gain/(loss) related to employee benefit plans	21.1	(39.5)	11.1
Reclassification of prior service (credit)/costs into employee compensation expense	0	(7)	(7.2)
Prior service credit related to employee benefit plans	0	(3.1)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	5.9	(5.5)	0
Reclassification of actuarial (gains)/losses into employee compensation expense	2.5	1.5	2.2
Share of other comprehensive income/(loss) of equity method investments	(0.5)	(1.1)	(0.6)
Unrealized gains/(losses) on available-for-sale investments	5.1	5.2	(6)
Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses	(5.4)	0.3	(0.4)
Accumulated other comprehensive income/(loss), net of tax:
Beginning balance	(809.3)	(446)	48.8
Other comprehensive income/(loss)	418.1	(363.3)	(494.8)
Ending balance	(391.2)	(809.3)	(446)
Equity method investments [Member]
Other comprehensive income/(loss), net of tax:
Share of other comprehensive income/(loss) of equity method investments	(0.5)	(1.1)	(0.6)
Accumulated other comprehensive income/(loss), net of tax:
Beginning balance	4.8	5.9	6.5
Other comprehensive income/(loss)	(0.5)	(1.1)	(0.6)
Ending balance	4.3	4.8	5.9
Foreign currency translation [Member]
Other comprehensive income/(loss), net of tax:
Currency translation differences on investments in foreign subsidiaries	389.4	(314.1)	(493.9)
Accumulated other comprehensive income/(loss), net of tax:
Beginning balance	(679.9)	(365.8)	128.1
Other comprehensive income/(loss)	389.4	(314.1)	(493.9)
Ending balance	(290.5)	(679.9)	(365.8)
Employee benefit plans [Member]
Other comprehensive income/(loss), net of tax:
Actuarial gain/(loss) related to employee benefit plans	21.1	(39.5)	11.1
Reclassification of prior service (credit)/costs into employee compensation expense		(7)	(7.2)
Prior service credit related to employee benefit plans	0	(3.1)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	5.9	(5.5)
Reclassification of actuarial (gains)/losses into employee compensation expense	2.5	1.5	2.2
Accumulated other comprehensive income/(loss), net of tax:
Beginning balance	(139.2)	(85.6)	(91.7)
Other comprehensive income/(loss)	29.5	(53.6)	6.1
Ending balance	(109.7)	(139.2)	(85.6)
Available-for-sale investments [Member]
Other comprehensive income/(loss), net of tax:
Unrealized gains/(losses) on available-for-sale investments	5.1	5.2	(6)
Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses	(5.4)	0.3	(0.4)
Accumulated other comprehensive income/(loss), net of tax:
Beginning balance	5	(0.5)	5.9
Other comprehensive income/(loss)	(0.3)	5.5	(6.4)
Ending balance	4.7	$ 5	$ (0.5)
Designated as Hedging Instrument [Member]
Other comprehensive income/(loss), net of tax:
Intercompany Foreign Currency Balance, Amount	$ 175.9			£ 130

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)awards$ / shares	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2015USD ($)$ / shares	May 31, 2016shares	May 31, 2010shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 175,300,000	$ 159,700,000	$ 150,300,000
Income tax benefit from share-based compensation agreements	48,900,000	44,700,000	43,800,000
Proceeds from Stock Options Exercised	$ 0	0	3,700,000
Number of Share Awards By Type | awards	2
Fair value of vested shares	$ 168,700,000	$ 128,400,000	$ 202,600,000
Weighted average fair value of shares granted | $ / shares	$ 32.23	$ 27.44	$ 39.99
Unrecognized compensation cost related to non-vested shares	$ 264,100,000
Weighted average non-vested shares compensation cost expected to recognize	2 years 5 months 6 days
ESPP discount rate	85.00%
Maximum employee ESPP contributions per offering period	$ 6,000
recognized expense for employee stock purchase	$ 900,000	$ 900,000	$ 900,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proportional vesting rate	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proportional vesting rate	100.00%
Global Equity Incentive Plan, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under share awards plan | shares				21,700,000
Global Equity Incentive Plan, 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under share awards plan | shares					3,000,000

Share-Based Compensation (Movem

Share-Based Compensation (Movements On Share Awards) (Details) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unvested at beginning of year Weighted Average Grant Date Fair Value	$ 31.22
Granted during period Weighted Average Grant Date Fair Value	32.23	$ 27.44	$ 39.99
Forfeited during the year Weighted Average Grant Date Fair Value	31.51
Vested and distributed during the period Weighted Average Grant Date Fair Value	31.53
Unvested at the end of the year Weighted Average Grant Date Fair Value	$ 31.52	$ 31.22
Time Vested N y s e [Member]
Unvested at the beginning of year	12.1	10.4	11.5
Granted during the year	5.3	6.5	4.1
Forfeited during the year	(0.4)	(0.3)	(0.2)
Vested and distributed during the year	(5)	(4.5)	(5)
Unvested at the end of the year	12	12.1	10.4
Performance Shares [Member]
Unvested at the beginning of year	0.8	0.6	0.5
Granted during the year	0.3	0.4	0.3
Forfeited during the year	0	0	0
Vested and distributed during the year	(0.2)	(0.2)	(0.2)
Unvested at the end of the year	0.9	0.8	0.6

Retirement Benefit Plans (Narra

Retirement Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined benefit plan, cost recognized	$ 73.1	$ 58.6	$ 58.4
Other postretirement benefits payable	26.2	23.1
Retirement Plans [Member]
Prior service cost/(credit)	3.9	$ 3.7
Estimated amounts of contributions expected to be paid to the plans in next fiscal year	$ 24.5

Retirement Benefit Plans (Sched

Retirement Benefit Plans (Schedule of defined benefit plan obligations and assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair value of plan assets	$ 486.9	$ 424.1
Retirement Plans [Member]
Benefit obligation	(548.6)	(521.2)	$ (490.7)
Fair value of plan assets	486.9	424.1	$ 422.7
Funded status	(61.7)	(97.1)
Amounts recognized in the Consolidated Balance Sheets:
Other assets	3.6	3.4
Accrued compensation and benefits	$ (65.3)	$ (100.5)

Retirement Benefit Plans (Chang

Retirement Benefit Plans (Changes in defined benefit plan obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Actuarial gain/(loss) related to employee benefit plans	$ 21.1	$ (39.5)	$ 11.1
Retirement Plans [Member]
Benefit obligation, beginning balance	521.2	490.7
Service cost	2.3	4.6	5.4
Interest cost	14.1	16.5	17.7
Actuarial gain/(loss) related to employee benefit plans	3.3	102.4
Exchange difference	(51.7)	73.5
Benefits paid	(9)	(13.8)
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	4.1
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0	(9.8)
Defined Benefit Plan, Plan Assets, Payment for Settlement	(35)	0
Benefit obligation, ending balance	$ 548.6	521.2	490.7
Medical Plan [Member]
Service cost		0	0
Interest cost		$ 0	$ 0

Retirement Benefit Plans (Sch80

Retirement Benefit Plans (Schedule of assumptions used to determine defined benefit obligations) (Details) - Retirement Plans [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Discount rate	2.47%	2.64%
Expected rate of salary increases	3.26%	3.26%
Future pension/medical cost trend rate increases	2.97%	2.98%

Retirement Benefit Plans (Cha81

Retirement Benefit Plans (Changes in the fair value of plan assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Beginning balance	$ 424.1
Ending balance	486.9	$ 424.1
Retirement Plans [Member]
Beginning balance	424.1	422.7
Actual return on plan assets	52.3	71
Exchange difference	41.9	(69.9)
Contributions from the company	11.8	14.2
Benefits paid	(9)	(13.9)
Settlement and other	(34.2)	0
Ending balance	$ 486.9	$ 424.1

Retirement Benefit Plans (Break

Retirement Benefit Plans (Breakdown of amount recognized in accumulated other comprehensive income) (Details) - Retirement Plans [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Prior service cost/(credit)	$ 3.9	$ 3.7
Net actuarial loss/(gain)	128.3	164.1
Total	$ 132.2	$ 167.8

Retirement Benefit Plans (Bre83

Retirement Benefit Plans (Breakdown of amounts in accumulated other comprehensive income expected to be amortized into net periodic benefit cost) (Details) (New) - Retirement Plans [Member] $ in Millions	Dec. 31, 2017USD ($)
Prior service cost/(credit)	$ 0.1
Net actuarial loss/(gain)	2.4
Total	$ 2.5

Retirement Benefit Plans (Sch84

Retirement Benefit Plans (Schedule of benefit obligations in excess of plan assets) (Details) - Retirement Plans [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accumulated benefit obligation	$ 539.4	$ 512.1
Fair value of plan assets	474.1	411.6
Projected benefit obligation	$ 539.4	$ 512.1

Retirement Benefit Plans (Compo

Retirement Benefit Plans (Components of net periodic benefit cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Plans [Member]
Service cost	$ 2.3	$ 4.6	$ 5.4
Interest cost	14.1	16.5	17.7
Expected return on plan assets	(22.6)	(21.7)	(22.9)
Amortization of prior service cost/(credit)	0.2	0	0.1
Amortization of net actuarial gain/(loss)	3	1.8	3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	7.3	0	0
Net periodic benefit cost	$ 4.3	1.2	3.3
Medical Plan [Member]
Service cost		0	0
Interest cost		0	0
Expected return on plan assets		0	0
Amortization of prior service cost/(credit)		(11.3)	(11.3)
Amortization of net actuarial gain/(loss)		(0.3)	(0.3)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement		(9)	0
Net periodic benefit cost		$ (20.6)	$ (11.6)

Retirement Benefit Plans (Sch86

Retirement Benefit Plans (Schedule of assumptions used to determine net periodic benefit cost) (Details) - Retirement Plans [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Discount rate	2.64%	3.69%	3.52%
Expected return on plan assets	5.01%	5.53%	5.90%
Expected rate of salary increases	3.26%	3.16%	3.06%
Future pension rate increases	2.98%	2.98%	2.88%

Retirement Benefit Plans (Analy

Retirement Benefit Plans (Analysis of plan assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair value of plan assets	$ 486.9	$ 424.1
Retirement Plans [Member]
Fair value of plan assets	$ 486.9	$ 424.1	$ 422.7
Percentage of plan assets	100.00%	100.00%
Cash and Cash Equivalents [Member]
Fair value of plan assets	$ 10.7	$ 3.9
Cash and Cash Equivalents [Member] | Retirement Plans [Member]
Fair value of plan assets	$ 10.7	$ 3.9
Percentage of plan assets	2.20%	0.90%
Fund Investments [Member]
Fair value of plan assets	$ 227.9	$ 207.4
Fund Investments [Member] | Retirement Plans [Member]
Fair value of plan assets	$ 227.9	$ 207.4
Percentage of plan assets	46.80%	48.90%
Equity Securities [Member]
Fair value of plan assets	$ 133.9	$ 122.1
Equity Securities [Member] | Retirement Plans [Member]
Fair value of plan assets	$ 133.9	$ 122.1
Percentage of plan assets	27.50%	28.80%
Government Debt Securities [Member]
Fair value of plan assets	$ 20.9	$ 73
Government Debt Securities [Member] | Retirement Plans [Member]
Fair value of plan assets	$ 20.9	$ 73
Percentage of plan assets	4.30%	17.20%
Other Assets [Member]
Fair value of plan assets	$ 80.1	$ 7.3
Other Assets [Member] | Retirement Plans [Member]
Fair value of plan assets	$ 13.4	$ 7.3
Percentage of plan assets	2.80%	1.70%
Guaranteed Investments Contracts [Member]
Fair value of plan assets	$ 13.4	$ 10.4
Guaranteed Investments Contracts [Member] | Retirement Plans [Member]
Fair value of plan assets	$ 80.1	$ 10.4
Percentage of plan assets	16.50%	2.50%

Retirement Benefit Plans (Sch88

Retirement Benefit Plans (Schedule of fair value of plan assets by three level fair value hierarchy) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Defined benefit plan, fair value of plan assets	$ 486.9	$ 424.1
Cash and Cash Equivalents [Member]
Defined benefit plan, fair value of plan assets	10.7	3.9
Fund Investments [Member]
Defined benefit plan, fair value of plan assets	227.9	207.4
Equity Securities [Member]
Defined benefit plan, fair value of plan assets	133.9	122.1
Government Debt Securities [Member]
Defined benefit plan, fair value of plan assets	20.9	73
Other Assets [Member]
Defined benefit plan, fair value of plan assets	80.1	7.3
Guaranteed Investments Contracts [Member]
Defined benefit plan, fair value of plan assets	13.4	10.4
Fair Value, Inputs, Level 1 [Member]
Defined benefit plan, fair value of plan assets	466.5	354.4
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined benefit plan, fair value of plan assets	10.7	3.9
Fair Value, Inputs, Level 1 [Member] | Fund Investments [Member]
Defined benefit plan, fair value of plan assets	227.9	207.4
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Defined benefit plan, fair value of plan assets	133.9	122.1
Fair Value, Inputs, Level 1 [Member] | Government Debt Securities [Member]
Defined benefit plan, fair value of plan assets	13.9	13.7
Fair Value, Inputs, Level 1 [Member] | Other Assets [Member]
Defined benefit plan, fair value of plan assets	80.1	7.3
Fair Value, Inputs, Level 1 [Member] | Guaranteed Investments Contracts [Member]
Defined benefit plan, fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member]
Defined benefit plan, fair value of plan assets	7	59.3
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined benefit plan, fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Fund Investments [Member]
Defined benefit plan, fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Defined benefit plan, fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Government Debt Securities [Member]
Defined benefit plan, fair value of plan assets	7	59.3
Fair Value, Inputs, Level 2 [Member] | Other Assets [Member]
Defined benefit plan, fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Guaranteed Investments Contracts [Member]
Defined benefit plan, fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) [Member]
Defined benefit plan, fair value of plan assets	13.4	10.4
Significant Unobservable Inputs (Level 3) [Member] | Cash and Cash Equivalents [Member]
Defined benefit plan, fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fund Investments [Member]
Defined benefit plan, fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Securities [Member]
Defined benefit plan, fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) [Member] | Government Debt Securities [Member]
Defined benefit plan, fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member]
Defined benefit plan, fair value of plan assets	$ 0	0
Significant Unobservable Inputs (Level 3) [Member] | Guaranteed Investments Contracts [Member]
Defined benefit plan, fair value of plan assets		$ 10.4

Retirement Benefit Plans (Recon

Retirement Benefit Plans (Reconciliation of beginning and ending fair value balances for assets with unobservable fair value inputs) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Beginning balance	$ 424.1
Ending balance	486.9
Significant Unobservable Inputs (Level 3) [Member]
Beginning balance	10.4
Ending balance	$ 13.4

Retirement Benefit Plans (Quant

Retirement Benefit Plans (Quantitative Information about Level 3 Fair Value Measurements) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value of plan assets	$ 486.9	$ 424.1
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value of plan assets	$ 13.4	$ 10.4

Retirement Benefit Plans (Sch91

Retirement Benefit Plans (Schedule of benefits expected to be paid in next five fiscal years and the five fiscal years thereafter) (Details) - Retirement Plans [Member] $ in Millions	Dec. 31, 2017USD ($)
Expected benefit payments [Abstract]
2,017	$ 9.3
2,018	9.6
2,019	10
2,020	10.3
2,021	10.6
Thereafter in the succeeding five years	$ 59.3

Operating Leases (Narrative) (D

Operating Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases [Abstract]
Operating Leases Expense	$ 54.3	$ 46.9	$ 45.7
Operating Leases, Income Statement, Sublease Revenue	$ 1	$ 10.9	$ 7.6

Operating Leases (Schedule of F

Operating Leases (Schedule of Future Commitments Under Non-Cancelable Operating Leases) (Details) $ in Millions	Dec. 31, 2017USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,018	$ 59.7
2,019	61.6
2,020	53.6
2,021	50.7
2,022	48.5
Thereafter	90.4
Gross lease commitments	364.5
Less: future minimum payments expected to be received under non-cancelable subleases	6.7
Net lease commitments	357.8
Building [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,018	57.6
2,019	59.6
2,020	51.6
2,021	49.8
2,022	48.5
Thereafter	90.4
Gross lease commitments	357.5
Less: future minimum payments expected to be received under non-cancelable subleases	6.7
Net lease commitments	350.8
Other [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,018	2.1
2,019	2
2,020	2
2,021	0.9
2,022	0
Thereafter	0
Gross lease commitments	7
Less: future minimum payments expected to be received under non-cancelable subleases	0
Net lease commitments	$ 7

Other Gains and Losses, Net (Sc

Other Gains and Losses, Net (Schedule of other gains and losses, net) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OTHER GAINS AND LOSSES, NET
Gain on sale of investments	$ 11.3	$ 1.5	$ 3.8
Net Realized and Unrealized Gain on Trading Securities	40.4	14.2	0
Unrealized Gain on Foreign Currency Derivatives, before Tax	0	22	0
Gain on contingent consideration liability	7.6	0	27.1
Foreign Currency Transaction Gain, before Tax	16.2	0	0
Other realized gains	0.2	1.4	0.9
Total other gains	75.7	39.1	31.8
Other-than-temporary impairment of available-for-sale investments	(3.2)	0	(2)
Net Realized and Unrealized Loss on Trading Securities	0	0	(13.5)
Loss Contingency Accrual	0	(7.4)	0
Net foreign exchange losses	0	(6)	(2.4)
Foreign exchange hedge loss	(21)	0	(7.7)
Realized loss on sale of partnerships	0	0	(7.3)
Other realized losses	0	(2.8)	(0.4)
Total other losses	(24.2)	(16.2)	(33.3)
Other gains and losses, net	$ 51.5	$ 22.9	$ (1.5)

Taxation (Narrative) (Details)

Taxation (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Expense (Benefit) per 2017 Tax Act		$ (130,700,000)
Tax benefit due to change in tax rate		130,700,000
Transition tax on foreign earnings		$ 0
Statutory tax rate		35.00%	35.00%	35.00%
Deferred Tax Assets, Operating Loss Carryforwards		$ 413,300,000	$ 243,800,000
Unremitted Foreign Earnings		988,000,000	897,200,000
Deferred Tax Liabilities, Undistributed Foreign Earnings		1,400,000	900,000
Unrecognized Tax Benefits		19,600,000	10,500,000	$ 9,600,000	$ 6,000,000
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations		3,100,000	0	0
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		16,500,000	9,500,000
Income tax provision		(268,200,000)	(338,300,000)	(398,000,000)
Expiring In Next Five Fiscal Years [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration		35,200,000
Expiring In After Five Fiscal Years [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration		15,200,000
Indefinite Life [Member]
Deferred Tax Assets, Operating Loss Carryforwards		362,900,000
Change during the period [Member]
Deferred Tax Assets, Increase (Decrease) in Operating Loss Carryforward		169,500,000
Operating Loss Carryforwards resulting from acquisitions [Member]
Deferred Tax Assets, Increase (Decrease) in Operating Loss Carryforward		160,100,000
Operating Loss Carryforwards resulting from FX [Domain]
Deferred Tax Assets, Increase (Decrease) in Operating Loss Carryforward		(23,100,000)
General Business Tax Credit Carryforward [Member]
Deferred Tax Assets, Increase (Decrease) in Operating Loss Carryforward		$ (15,800,000)
Forfeiture of losses resulting from liquidations or mergers [Member]
Deferred Tax Assets, Increase (Decrease) in Operating Loss Carryforward	$ 30,000,000
Canada
Dividends Withholding Tax Rate		5.00%
ILLINOIS
Unrecognized Tax Benefits, Period Increase (Decrease)		$ 11,000,000
Related to accrued interest and penalties [Member]
Income Tax Examination, Penalties and Interest Accrued		2,900,000	1,700,000	1,200,000
Income tax provision		(1,200,000)	$ (500,000)	$ (900,000)
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound		0
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound		$ 10,000,000

Taxation (Summary of (Provision

Taxation (Summary of (Provision) Benefit for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal	$ (147.5)	$ (161)	$ (221)
State	(30.2)	(18.9)	(23.4)
Foreign	(142.2)	(143)	(161.4)
Current income tax (provision)	(319.9)	(322.9)	(405.8)
Federal	63	(21.1)	11.9
State	(11.2)	(0.9)	(5.2)
Foreign	(0.1)	6.6	1.1
Deferred income tax (provision)	51.7	(15.4)	7.8
Total income tax (provision)	$ (268.2)	$ (338.3)	$ (398)

Taxation (Schedule of Deferred

Taxation (Schedule of Deferred Tax Recognized on Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets	$ 234.8	$ 328.2
Valuation allowance	(94.7)	(59)
Deferred tax assets, net of valuation allowance	140.1	269.2
Total deferred tax liabilities	(416.3)	(559.9)
Deferred Tax Liabilities, Net	(276.2)	(290.7)
Deferred Compensation Arrangements [Member]
Deferred tax assets	57.6	79.1
Accrued Rent Expenses [Member]
Deferred tax assets	7.2	12.3
Tax Loss Carryforwards [Member]
Deferred tax assets	94.6	64.8
Postretirement Medical, Pension and Other Benefits [Member]
Deferred tax assets	16.6	24.4
Investment Basis Differences [Member]
Deferred tax assets	32.8	58.3
Accrued bonus [Member]
Deferred tax assets	8.8	64.8
Other Deferred Tax Assets [Member]
Deferred tax assets	17.2	24.5
Deferred Sales Commissions [Member]
Total deferred tax liabilities	(11)	(13.5)
Goodwill and Intangibles [Member]
Total deferred tax liabilities	(377.3)	(509.6)
Revaluation Reserve [Member]
Total deferred tax liabilities	(19.2)	(27.6)
Other Deferred Tax Liability [Member]
Total deferred tax liabilities	$ (8.8)	$ (9.2)

Taxation (Reconciliation Betwee

Taxation (Reconciliation Between Statutory and Effective Tax Rates on Income from Operations) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Statutory Rate	35.00%	35.00%	35.00%
Foreign jurisdiction statutory income tax rates	(9.60%)	(8.10%)	(9.20%)
State taxes, net of federal tax effect	2.20%	1.60%	1.60%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	(9.30%)	0.00%	0.00%
Change in valuation allowance for unrecognized tax losses	0.40%	(0.40%)	(0.10%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent	(0.30%)	0.00%	0.00%
Other	1.20%	0.30%	1.80%
(Gains)/losses attributable to noncontrolling interests	(0.80%)	(0.40%)	0.10%
Effective tax rate per Consolidated Statements of Income	18.80%	28.00%	29.20%

Taxation (Income Before Taxes)

Taxation (Income Before Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	$ 1,429.2	$ 1,206.6	$ 1,362.1
Domestic Tax Authority [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	638.5	539.9	687.9
Foreign Tax Authority [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	790.7	666.7	674.2
Separate Institutional Accounts [Member] | Domestic Tax Authority [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	638.4	537.5	661.9
Separate Institutional Accounts [Member] | Foreign Tax Authority [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	754.8	652	746.3
Consolidated Investment Products [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	36	17.1	(46.1)
Consolidated Investment Products [Member] | Domestic Tax Authority [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	0.1	2.4	26
Consolidated Investment Products [Member] | Foreign Tax Authority [Member]
Schedule of Income Before Taxes, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	$ 35.9	$ 14.7	$ (72.1)

Taxation (Reconciliation of Cha

Taxation (Reconciliation of Changes in Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Balance	$ 10.5	$ 9.6	$ 6
Additions for tax positions related to the current year	0.9	0.9	2.5
Additions for tax positions related to prior years	11.5	0.1	2.2
Other reductions for tax positions related to prior years	(0.2)	(0.1)	(1.1)
Reductions for statute closings	(3.1)	0	0
Balance	$ 19.6	$ 10.5	$ 9.6

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - shares shares in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Contingently issuable share excluded	0.1	0.2	0.4

Earnings Per Share (Calculation

Earnings Per Share (Calculation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Income from continuing operations, net of taxes	$ 1,161	$ 868.3	$ 964.1
Net (income)/loss attributable to noncontrolling interests in consolidated entities	(33.7)	(14.1)	4
Net income attributable to Invesco Ltd. for basic and diluted EPS calculations	1,127.3	854.2	968.1
Net income attributable to Invesco Ltd.	1,127.3	854.2	968.1
Allocation of earnings to restricted shares	(33.7)	(24.8)	(24.6)
Net income attributable to common shareholders	$ 1,093.6	$ 829.4	$ 943.5
Weighted average shares outstanding - basic (in shares)	409.4	414.7	428.9
Weighted Average Number of Shares, Restricted Stock	(12.2)	(12.1)	(10.9)
Weighted Average Number of Shares Outstanding, Basic - Common shareholders	397.2	402.6	418
Dilutive effect on share-based awards (in shares)	0.5	0.3	0.4
Weighted Average Number of Shares Outstanding, Diluted - Common shares	397.7	402.9	418.4
Weighted average shares outstanding - diluted (in shares)	409.9	415	429.3
Earnings per share:
Basic earnings per share (usd per share)	$ 2.75	$ 2.06	$ 2.26
Diluted earnings per share:
Diluted earnings per share (usd per share)	$ 2.75	$ 2.06	$ 2.26

Geographic Information (Details

Geographic Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ (5,160.3)	$ (4,734.4)	$ (5,122.9)
Long-lived assets	490.7	464.7	426.9
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(2,742.3)	(2,517.2)	(2,613.5)
Long-lived assets	332.2	331.6	306.7
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(1,078.6)	(1,029.9)	(1,267.4)
Long-lived assets	118.3	95.9	88.3
Continental Europe/Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(756.6)	(637.9)	(675.2)
Long-lived assets	10	10.7	6.8
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(322.1)	(315.2)	(346.9)
Long-lived assets	8.9	9.4	10
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(260.7)	(234.2)	(219.9)
Long-lived assets	21.3	17.1	15.1
Inter-company revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Inter-company revenue | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	5.6	27	8.6
Inter-company revenue | United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(122.8)	(99)	(114.4)
Inter-company revenue | Continental Europe/Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	243	188.9	216.7
Inter-company revenue | Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	16.9	10.3	7
Inter-company revenue | Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(142.7)	(127.2)	(117.9)
External Customers [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(5,160.3)	(4,734.4)	(5,122.9)
External Customers [Member] | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(2,747.9)	(2,544.2)	(2,622.1)
External Customers [Member] | United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(955.8)	(930.9)	(1,153)
External Customers [Member] | Continental Europe/Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(999.6)	(826.8)	(891.9)
External Customers [Member] | Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	(339)	(325.5)	(353.9)
External Customers [Member] | Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ (118)	$ (107)	$ (102)

Commitments And Contingencies (

Commitments And Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Undrawn capital and purchase commitments	$ 292.8	$ 204.1
Purchase Commitment, Description	1.2
Letter of Credit [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 7.8

Consolidated Investment Prod105

Consolidated Investment Products (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)voting_interest_entity	Dec. 31, 2017USD ($)variable_interest_entity	Dec. 31, 2016USD ($)variable_interest_entity
Variable Interest Entity [Line Items]
Variable Interest Entity Unavailability of Information Number of Entities No Longer Consolidated				1	8	10
Deconsolidation, Gain (Loss), Amount			$ 0			$ 0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 227,300,000	$ 227,300,000	227,300,000	$ 227,300,000	$ 227,300,000	$ 234,400,000
Collateralized Loan Obligations Terms Of Arrangements Interest Rate Margin Spread High		10.00%
Collateral Assets Default Percentage		0.41%				0.30%
Notes Issued By Collateralized Loan Obligations Terms Of Arrangements Interest Rate Margin Spread Low		0.92%
Notes Issued By Collateralized Loan Obligations Terms Of Arrangements Interest Rate Margin Spread High		8.25%
Variable Interest Entity Consolidated Number of Entities | variable_interest_entity					19
CLO [Member]
Variable Interest Entity [Line Items]
Issued Note Maturity Average Years	10 years
Senior Secured Bank Loans And Bonds [Member] | CLO [Member]
Variable Interest Entity [Line Items]
Fair Value, Option, Aggregate Differences, Long-term Debt Instruments	$ 84,600,000	$ 84,600,000	84,600,000	84,600,000	$ 84,600,000	$ 96,600,000
Minimum [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Term	7 years
Maximum [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Term	12 years
Consolidation, Eliminations [Member] | Bank Loan Obligations [Member] | CLO [Member]
Variable Interest Entity [Line Items]
Collateralized Loan Obligation, Collateral Assets	$ 4,859,300,000	$ 4,859,300,000	$ 4,859,300,000	$ 4,859,300,000	$ 4,859,300,000	$ 4,397,800,000

Consolidated Investment Prod106

Consolidated Investment Products (Balances Related To CIP) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Consolidated Investment Products [Abstract]
Cash and cash equivalents of consolidated investment products	$ 511.3	$ 742.2
Accounts receivable and other assets of CIP	131.5	106.2
Investments Of Consolidated Investment Products	5,658	5,116.1
Long Term Debt Of Consolidated Investment Products	(4,799.8)	(4,403.1)
Other liabilities of consolidated investment products	(498.8)	(673.4)
Retained earnings	16.7	19
CIP adjustment to accumulated other comprehensive income, net of tax	(16.6)	(18)
Redeemable Noncontrolling Interest, Consolidated Investment Products	(243.2)	(283.7)
Nonredeemable Noncontrolling Interest, Consolidated Investment Products	(258.6)	(107.2)
Net Interests In Consolidated Investment Products	$ 500.5	$ 498.1

Consolidated Investment Prod107

Consolidated Investment Products (VIE Balance Sheets Consolidated In Period) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	$ 511.3	$ 742.2
Accounts receivable and other assets of CIP	131.5	106.2
Investments of CIP	5,658	5,116.1
Total assets	31,668.8	25,734.3
Debt of CIP	(4,799.8)	(4,403.1)
Other liabilities of CIP	(498.8)	(673.4)
Total liabilities	22,470	17,838.8
Total equity	8,955.6	7,611.8	$ 8,695.7	$ 9,119.8
Total liabilities, temporary and permanent equity	31,668.8	25,734.3
CLOs - VIEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	15.8	40.1
Accounts receivable and other assets of CIP	4.1	19
Investments of CIP	358.1	418
Total assets	378	477.1
Debt of CIP	(4.2)	0
Other liabilities of CIP	(3.1)	(23.9)
Total liabilities	7.3	23.9
Total equity	370.7	453.2
Total liabilities, temporary and permanent equity	378	477.1
VOEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	0
Accounts receivable and other assets of CIP	0.2
Investments of CIP	49.8
Total assets	50
Debt of CIP	0
Other liabilities of CIP	0
Total liabilities	0
Total equity	50
Total liabilities, temporary and permanent equity	50
Consolidated Entities [Member] | CLOs - VIEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP	277.8	609.8
Accounts receivable and other assets of CIP	11.5	108.5
Investments of CIP	851.8	1,032.8
Total assets	1,141.1	1,751.1
Debt of CIP	(544.2)	(1,013.3)
Other liabilities of CIP	(331.5)	(472.4)
Total liabilities	875.7	1,485.7
Total equity	265.4	265.4
Total liabilities, temporary and permanent equity	$ 1,141.1	1,751.1
Consolidated Entities [Member] | VOEs [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents of CIP		0
Accounts receivable and other assets of CIP		0.2
Investments of CIP		49.8
Total assets		50
Debt of CIP		0
Other liabilities of CIP		0
Total liabilities		0
Total equity		50
Total liabilities, temporary and permanent equity		$ 50

Consolidated Investment Prod108

Consolidated Investment Products (Condensed Consolidating Statement Of Income Line Items Reflecting Impact Of Consolidation Of Investment Products Into The Condensed Consolidated Statements Of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues	$ (5,160.3)	$ (4,734.4)	$ (5,122.9)
Total operating expenses	3,883.2	3,558	3,764.5
Operating income	(1,277.1)	(1,176.4)	(1,358.4)
Equity in earnings of unconsolidated affiliates	(44.7)	(9.3)	(35.1)
Interest and dividend income	(13.4)	(12.2)	(13)
Other gains and losses, net	(51.5)	(22.9)	1.5
Other gains/(losses) of CIP, net	137.3	79.2	27.1
Income before income taxes	1,429.2	1,206.6	1,362.1
Income tax provision	(268.2)	(338.3)	(398)
Income from continuing operations, net of income taxes	1,161	868.3	964.1
Net income	1,161	868.3	964.1
(Gains)/losses attributable to noncontrolling interests in consolidated entities, net	(33.7)	(14.1)	4
Net income attributable to Invesco Ltd.	1,127.3	854.2	968.1
Impact of CIP [Member]
Revenues	32.4	22.3	39.2
Total operating expenses	10.5	28.7	24
Operating income	42.9	51	63.2
Equity in earnings of unconsolidated affiliates	20	8.9	1.7
Interest and dividend income	0	0.3	4.4
Other gains and losses, net	38.4	1.9	3.9
Interest and dividend income of CIP	211.6	195.3	253
Interest expense of CIP	(155.3)	(123.5)	(188.9)
Other gains/(losses) of CIP, net	81	7.4	(37)
Income before income taxes	36	17.1	(46.1)
Income tax provision	0	0	0
Net income	36	17.1	(46.1)
(Gains)/losses attributable to noncontrolling interests in consolidated entities, net	(33.7)	(14.1)	5.7
Net income attributable to Invesco Ltd.	$ 2.3	$ 3	$ (40.4)

Consolidated Investment Prod109

Consolidated Investment Products (Fair Value Hierarchy Levels Of Investments Held And Notes Issued By Consolidated Investment Products) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Investments Of Consolidated Investment Products	$ 5,658	$ 5,116.1
CLO notes	(22,470)	(17,838.8)
Real Estate Investments, Net	76.2	40.7
Investment in master fund		57.7
Fair Value, Inputs, Level 1 [Member]
Investments Of Consolidated Investment Products	217.8	179
Real Estate Investments, Net	0	0
Investment in master fund		0
Fair Value, Inputs, Level 2 [Member]
Investments Of Consolidated Investment Products	5,200.6	4,770.1
Real Estate Investments, Net	0	0
Investment in master fund		0
Significant Unobservable Inputs (Level 3) [Member]
Investments Of Consolidated Investment Products	76.2	40.7
Real Estate Investments, Net	76.2	40.7
Investment in master fund		0
Bank Loans [Member]
CLO Collateral Assets	4,894.2	4,397.8
Bank Loans [Member] | Fair Value, Inputs, Level 1 [Member]
CLO Collateral Assets	0	0
Bank Loans [Member] | Fair Value, Inputs, Level 2 [Member]
CLO Collateral Assets	4,894.2	4,397.8
Bank Loans [Member] | Significant Unobservable Inputs (Level 3) [Member]
CLO Collateral Assets	0	0
Bonds [Member]
CLO Collateral Assets	302	370.9
Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
CLO Collateral Assets	0	166
Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
CLO Collateral Assets	302	370.9
Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member]
CLO Collateral Assets	0	0
Equity Securities [Member]
CLO Collateral Assets	203.2	167.4
Private Equity Fund Assets	19	13
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
CLO Collateral Assets	198.8
Private Equity Fund Assets	19	13
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
CLO Collateral Assets	4.4	1.4
Private Equity Fund Assets	0	0
Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
CLO Collateral Assets	0
Private Equity Fund Assets	0	0
Private Equity Funds [Member]
Private Equity Fund Assets	163.4	68.6
Private Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Private Equity Fund Assets	0	0
Private Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Private Equity Fund Assets	0	0
Private Equity Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Private Equity Fund Assets	0	0
Portion at Other than Fair Value Measurement [Member]
Investments Of Consolidated Investment Products	163.4	126.3
Real Estate Investments, Net	0	0
Investment in master fund		57.7
Portion at Other than Fair Value Measurement [Member] | Bank Loans [Member]
CLO Collateral Assets	0	0
Portion at Other than Fair Value Measurement [Member] | Bonds [Member]
CLO Collateral Assets	0	0
Portion at Other than Fair Value Measurement [Member] | Equity Securities [Member]
CLO Collateral Assets	0
Private Equity Fund Assets	0	0
Portion at Other than Fair Value Measurement [Member] | Private Equity Funds [Member]
Private Equity Fund Assets	$ 163.4	$ 68.6

Consolidated Investment Prod110

Consolidated Investment Products (Beginning And Ending Fair Value Measurements For Level 3 Assets And Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net unrealized gains/losses attributable to investments	$ 24.5	$ 1.3
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance (Asset)	40.7	388.6
Purchases (Asset)	15.1	39.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(4.5)	0
Net unrealized gains and losses included in other gains and losses (Liability)	24.9	1.3
Ending balance (Asset)	76.2	40.7	$ 388.6
Accounting Standards Update 2015-02 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ (733.5)
Accounting Standards Update 2015-02 [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Increase (Decrease) for Accounting Pronouncements	$ 0	$ 388.6

Consolidated Investment Prod111

Consolidated Investment Products (Level 3 Valuation Techniques) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Real Estate Investments, Net	$ 76,200,000	$ 40,700,000
Fair Value Inputs, Discount Rate	3.89%
Deconsolidation, Gain (Loss), Amount	$ 0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Real Estate Investments, Net	$ 76,200,000	40,700,000
Private Market Transactions [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Real Estate Investments, Net		$ 40,700,000
Discounted Cash Flow Technique | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	7.00%
Fair Value Inputs, Cap Rate	5.30%
Fair Value Inputs, Long-term Revenue Growth Rate	2.00%
Discounted Cash Flow Technique | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	33.00%
Fair Value Inputs, Cap Rate	0.00%
Fair Value Inputs, Long-term Revenue Growth Rate	3.00%
Discounted Cash Flow Technique | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	17.00%
Fair Value Inputs, Cap Rate	5.30%
Fair Value Inputs, Long-term Revenue Growth Rate	2.50%

Consolidated Investment Prod112

Consolidated Investment Products (Private Equity) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Private Equity Funds [Member]
Schedule of Investments [Line Items]
Fair Value	$ 163.4	$ 68.6
Unfunded Commitments	53.9	41.9
Investment in master fund [Member]
Schedule of Investments [Line Items]
Fair Value	0	57.7
Unfunded Commitments	$ 0	$ 0

Related Parties (Details)

Related Parties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment Advisory Fees	$ 4,126.6	$ 3,773.1	$ 4,061.1
Distribution and Servicing Fees	852.8	823.6	855.4
Performance Fees	113.3	44.3	85.9
Revenue, Other Financial Services	67.6	93.4	120.5
Revenues	5,160.3	4,734.4	5,122.9
Cash and cash equivalents	2,006.4	1,328	1,851.4	$ 1,514.2
Unsettled fund receivables	793.8	672.9
Accounts receivable	622.5	544.2
Investments	674.6	795.3
Separate Account Assets	12,444.5	8,224.2
Other assets	61.7	95
Total assets	31,668.8	25,734.3
Accrued compensation and benefits	696.1	654.3
Accounts payable and accrued expenses	895.7	812.4
Unsettled fund payables	783.8	659.3
Total liabilities	22,470	17,838.8
Affiliated Entity [Member]
Investment Advisory Fees	3,624.7	3,274.3	3,565.8
Distribution and Servicing Fees	851.2	822.3	854
Performance Fees	73.8	21.5	29.2
Revenue, Other Financial Services	59.1	79.8	108.5
Revenues	4,608.8	4,197.9	$ 4,557.5
Cash and cash equivalents	875.5	476.2
Unsettled fund receivables	204	253.2
Accounts receivable	359.9	344.4
Investments	608.5	728.3
Separate Account Assets	12,444.2	8,224.2
Other assets	9.2	2.9
Total assets	14,501.3	10,029.2
Accrued compensation and benefits	90.7	76.5
Accounts payable and accrued expenses	64.5	94.7
Unsettled fund payables	288.8	318.7
Total liabilities	$ 444	$ 489.9

Business optimization (Details)

Business optimization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Business optimization charges as part of operating expenses	$ 58	$ 49.9	$ 16.2
Incremental implementation costs - business optimization	35
Property, office and technology expenses [Member]
Restructuring Cost and Reserve [Line Items]
Business optimization charges as part of operating expenses	2.7
General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Business optimization charges as part of operating expenses	25.3
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Business optimization charges as part of operating expenses	$ 30

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Jan. 26, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Dividends declared per share		$ 1.15	$ 1.11	$ 1.06
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends declared per share	$ 0.29