XML 102 R9999.htm IDEA: XBRL DOCUMENT
v3.19.1

Label | Element | Value
--- | --- | ---
Retained Earnings [Member] |  |
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect | amg_TaxCutsandJobsActReclassificationfromAOCItoRetainedEarningsTaxEffect | $ (6,600,000)

X
- Definition Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect + References No definition available. + Details
Name: | amg_TaxCutsandJobsActReclassificationfromAOCItoRetainedEarningsTaxEffect
Namespace Prefix: | amg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |