Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2021

The carrying amount of goodwill at March 31, 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 three-month period ended March 31, 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		269.5			19.0		—		288.5
Goodwill adjustments due to appraisals and other acquisition adjustments		52.1			—		—		52.1
Goodwill written-off related to sales of business and impairment		(1.0	)		—		—		(1.0	)
Foreign currency translation adjustments during the period		43.9			0.4		—		44.3
Balance as of March 31, 2021	$	6,418.1		$	89.9	$	2.9	$	6,510.9

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

	March 31,			December 31,
	2021			2020
Expiration lists	$	4,937.9		$	4,753.2
Accumulated amortization - expiration lists		(2,546.9	)		(2,436.7	)
		2,391.0			2,316.5
Non-compete agreements		88.1			75.9
Accumulated amortization - non-compete agreements		(60.0	)		(57.8	)
		28.1			18.1
Trade names		104.4			107.8
Accumulated amortization - trade names		(44.7	)		(42.5	)
		59.7			65.3
Net amortizable assets	$	2,478.8		$	2,399.9

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