CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Consolidated revenue	$ 493.2	$ 500.3	$ 989.8	$ 1,000.3
Consolidated expenses:
Compensation and related expenses	263.7	215.3	494.1	455.7
Selling, general and administrative	95.7	89.4	190.4	181.1
Intangible amortization and impairments	6.3	7.3	89.6	14.5
Interest expense	34.5	33.5	68.6	63.4
Depreciation and other amortization	2.5	3.1	5.3	6.1
Other expenses (net)	10.0	10.8	21.6	19.9
Total consolidated expenses	412.7	359.4	869.6	740.7
Equity method income (net)	65.6	18.1	140.9	135.7
Investment and other income	25.5	19.3	37.1	37.2
Income before income taxes	171.6	178.3	298.2	432.5
Income tax expense	35.7	43.3	63.1	98.7
Net income	135.9	135.0	235.1	333.8
Net income (non-controlling interests)	(51.6)	(59.0)	(78.5)	(108.0)
Net income (controlling interest)	$ 84.3	$ 76.0	$ 156.6	$ 225.8
Average shares outstanding (basic) (in shares)	28.5	31.5	28.9	32.1
Average shares outstanding (diluted) (in shares)	31.4	35.3	32.3	36.0
Earnings per share (basic) (in dollars per share)	$ 2.96	$ 2.42	$ 5.43	$ 7.02
Earnings per share (diluted) (in dollars per share)	$ 2.80	$ 2.26	$ 5.01	$ 6.49

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.