Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2021

The carrying amount of goodwill at September 30, 2021 and December 31, 2020 allocated by domestic and foreign operations is as follows (in millions):

The changes in the carrying amount of goodwill for the nine-month period ended September 30, 2021 are as follows (in millions):

	Brokerage			Risk Management			Corporate		Total
Balance as of December 31, 2020	$	6,053.6		$	70.5		$	2.9	$	6,127.0
Goodwill acquired during the period		421.9			31.6			—		453.5
Goodwill adjustments due to appraisals and other acquisition adjustments		50.5			—			—		50.5
Goodwill written-off related to sales of business and impairment		(1.0	)		—			—		(1.0	)
Foreign currency translation adjustments during the period		(2.2	)		(0.3	)		—		(2.5	)
Balance as of September 30, 2021	$	6,522.8		$	101.8		$	2.9	$	6,627.5

Major classes of amortizable intangible assets at September 30, 2021 and December 31, 2020 consist of the following (in millions):

	September 30,			December 31,
	2021			2020
Expiration lists	$	4,997.2		$	4,753.2
Accumulated amortization - expiration lists		(2,727.5	)		(2,436.7	)
		2,269.7			2,316.5
Non-compete agreements		73.5			75.9
Accumulated amortization - non-compete agreements		(61.9	)		(57.8	)
		11.6			18.1
Trade names		105.5			107.8
Accumulated amortization - trade names		(47.8	)		(42.5	)
		57.7			65.3
Net amortizable assets	$	2,339.0		$	2,399.9

Estimated aggregate amortization expense for each of the next five years and thereafter is as follows (in millions):