Long-Term Debt (Schedule Of Long-Term Debt Instruments) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Line of Credit Facility, Expiration Date	Aug. 07, 2020
Unsecured Debt [Member] \| Due November 30, 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Nov. 30, 2022
Debt instrument, interest rate, stated percentage	3.125%
Debt Instrument, Face Amount	$ 600.0
Unsecured Debt [Member] \| Due January 30, 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Jan. 30, 2024
Debt instrument, interest rate, stated percentage	4.00%
Debt Instrument, Face Amount	$ 600.0
Unsecured Debt [Member] \| Due January 15, 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Jan. 15, 2026
Debt instrument, interest rate, stated percentage	3.75%
Debt Instrument, Face Amount	$ 500.0
Unsecured Debt [Member] \| Due November 30, 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Nov. 30, 2043
Debt instrument, interest rate, stated percentage	5.375%
Debt Instrument, Face Amount	$ 400.0
Carrying Value [Member]
Debt Instrument [Line Items]
Long-term Debt	2,076.4	$ 2,075.8
Carrying Value [Member] \| Line of Credit
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	0.0	0.0
Carrying Value [Member] \| Unsecured Debt [Member] \| Due November 30, 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt	597.0	596.9
Carrying Value [Member] \| Unsecured Debt [Member] \| Due January 30, 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt	594.3	594.0
Carrying Value [Member] \| Unsecured Debt [Member] \| Due January 15, 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt	495.2	495.1
Carrying Value [Member] \| Unsecured Debt [Member] \| Due November 30, 2043 [Member]
Debt Instrument [Line Items]
Long-term Debt	389.9	389.8
Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt	2,180.2	2,258.1
Fair Value [Member] \| Line of Credit
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	0.0	0.0
Fair Value [Member] \| Unsecured Debt [Member] \| Due November 30, 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt	603.6	608.8
Fair Value [Member] \| Unsecured Debt [Member] \| Due January 30, 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt	617.9	634.7
Fair Value [Member] \| Unsecured Debt [Member] \| Due January 15, 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt	501.4	515.0
Fair Value [Member] \| Unsecured Debt [Member] \| Due November 30, 2043 [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 457.3	$ 499.6

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=ivz_SeniorNotesDueJanuary302024Member
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- Details

Name:	us-gaap_DebtInstrumentAxis=ivz_SeniorNotesDueJanuary152026MemberMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=ivz_SeniorNotesDueNovember302043Member
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- Details

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Data Type:	na
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
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- Details

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