CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Income Statement [Abstract]
Consolidated revenue	$ 496.6	$ 499.9
Consolidated expenses:
Compensation and related expenses	230.3	240.4
Selling, general and administrative	94.7	91.7
Intangible amortization and impairments	83.3	7.3
Interest expense	34.1	29.9
Depreciation and other amortization	2.8	3.0
Other expenses (net)	11.7	9.0
Total consolidated expenses	456.9	381.3
Equity method income (net)	75.3	117.5
Investment and other income	11.6	18.0
Income before income taxes	126.6	254.1
Income tax expense	27.4	55.4
Net income	99.2	198.7
Net income (non-controlling interests)	(26.8)	(48.9)
Net income (controlling interest)	$ 72.4	$ 149.8
Average shares outstanding (basic) (in shares)	29.2	32.8
Average shares outstanding (diluted) (in shares)	32.6	40.1
Earnings per share (basic) (in dollars per share)	$ 2.48	$ 4.56
Earnings per share (diluted) (in dollars per share)	$ 2.20	$ 4.14

Amortization and Impairments of Intangible Assets

No definition available.

Name:	amg_AmortizationandImpairmentsofIntangibleAssets
Namespace Prefix:	amg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate expense charged against earnings to allocate the cost of tangible assets to periods in which the assets are used and held and to allocate the cost of issuing debt to periods in which the debt is outstanding. As a noncash expense, this element is added back to net income when calculating cash provided by (used in) operations using the indirect method.

+ References

No definition available.