XML 19 R64.htm IDEA: XBRL DOCUMENT
v3.19.3

Equity Method Investments in Affiliates - Change in Equity Method Investments (Details) - USD ($) $ in Millions | 9 Months Ended
--- | ---
Sep. 30, 2019 | Sep. 30, 2018
Change in Equity Method Investments in Affiliates [Roll Forward] |  |
Balance, as of December 31, 2018 | $ 2,791.0 |
Distributions of earnings | (210.4) | $ (410.3)
Investments in Affiliates | 162.3 | $ 7.3
Balance, as of September 30, 2019 | 2,359.7 |
Equity Method Investee |  |
Change in Equity Method Investments in Affiliates [Roll Forward] |  |
Balance, as of December 31, 2018 | 2,791.0 |
Earnings | 210.6 |
Intangible amortization and impairments | (529.1) |
Distributions of earnings | (210.4) |
Foreign currency translation | (22.5) |
Investments in Affiliates | 162.3 |
Divestments of Affiliates | (28.8) |
Other | (13.4) |
Balance, as of September 30, 2019 | $ 2,359.7 |

X
- Definition Change in Equity Method Investments in Affiliates + References No definition available. + Details
Name: | amg_ChangeinEquityMethodInvestmentsinAffiliatesRollForward
Namespace Prefix: | amg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity Method Investment, Intangible Asset Amortization and Impairments + References No definition available. + Details
Name: | amg_EquityMethodInvestmentIntangibleAssetAmortizationandImpairments
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Equity Method Investment, Other Increase (Decrease) + References No definition available. + Details
Name: | amg_EquityMethodInvestmentOtherIncreaseDecrease
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Equity Method Investment, Realized Gain (Loss) on Foreign Currency Translation + References No definition available. + Details
Name: | amg_EquityMethodInvestmentRealizedGainLossonForeignCurrencyTranslation
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Income (Loss) from Equity Method Investments Before Amortization of Intangibles + References No definition available. + Details
Name: | amg_IncomeLossfromEquityMethodInvestmentsBeforeAmortizationofIntangibles
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(10)) -URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(12)) -URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 21D -URI http://asc.fasb.org/extlink&oid=118932676&loc=SL94080555-108585 + Details
Name: | us-gaap_EquityMethodInvestmentDividendsOrDistributions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the entity's equity method investment which has been sold. + References No definition available. + Details
Name: | us-gaap_EquityMethodInvestmentSoldCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of investment in equity method investee and investment in and advance to affiliate. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_EquityMethodInvesteeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |