XML 29 R58.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2

Investments in Affiliates and Affiliate Sponsored Investment Products - Affiliate Accounted For Under Equity Method (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Equity method investments in Affiliates (net)	$ 2,195.6	$ 2,791.0
Carrying amount and maximum exposure to loss of equity method affiliates	352.6	513.2
Affiliates accounted for under the equity method
Variable Interest Entity [Line Items]
Unconsolidated VIE Net Assets	1,141.4	1,102.9
Carrying Value and Maximum Exposure to Loss	$ 1,843.0	$ 2,277.8

X

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 25
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8813-108599

Reference 3: 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_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

Difference between the carrying amount of assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the variable interest entity (VIE) and the reporting entity's maximum exposure to loss as a result of its involvement with the VIE, where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685

+ Details

Name:	us-gaap_VariableInterestDifferenceBetweenCarryingAmountAndMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

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

X

- Definition

Net carrying amount of the assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), when the reporting entity is not the VIE's primary beneficiary.

+ References

No definition available.

+ Details

Name:	us-gaap_VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=amg_VariableInterestEntitiesPreviouslyAccountedforUndertheEquityMethodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: