Intangible Assets

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

7. Intangible Assets

The carrying amount of goodwill at December 31, 2019 and 2018 allocated by domestic and foreign operations is as follows (in millions):

			Risk
	Brokerage		Management		Corporate		Total
At December 31, 2019
United States	$	3,163.8	$	33.1	$	—	$	3,196.9
United Kingdom		1,177.8		12.9		—		1,190.7
Canada		454.4		—		—		454.4
Australia		416.5		10.5		—		427.0
New Zealand		208.0		10.1		—		218.1
Other foreign		128.4		—		3.0		131.4
Total goodwill - net	$	5,548.9	$	66.6	$	3.0	$	5,618.5
At December 31, 2018
United States	$	2,715.3	$	29.6	$	—	$	2,744.9
United Kingdom		753.7		9.2		—		762.9
Canada		378.6		—		—		378.6
Australia		406.3		0.3		—		406.6
New Zealand		209.6		10.2		—		219.8
Other foreign		110.1		—		2.7		112.8
Total goodwill - net	$	4,573.6	$	49.3	$	2.7	$	4,625.6

78

The changes in the carrying amount of goodwill for 2019 and 2018 are as follows (in millions):

				Risk
	Brokerage			Management			Corporate			Total
Balance as of December 31, 2017	$	4,119.2		$	42.6		$	3.0		$	4,164.8
Goodwill acquired during the year		574.7			9.9			—			584.6
Goodwill adjustments related to appraisals and other acquisition adjustments		2.2			(2.3	)		—			(0.1	)
Foreign currency translation adjustments during the year		(122.5	)		(0.9	)		(0.3	)		(123.7	)
Balance as of December 31, 2018		4,573.6			49.3			2.7			4,625.6
Goodwill acquired during the year		958.4			16.9			0.4			975.7
Goodwill adjustments related to appraisals and other acquisition adjustments		0.2			(0.2	)		—			—
Goodwill written-off related to sales of business		(7.2	)		—			—			(7.2	)
Foreign currency translation adjustments during the year		23.9			0.6			(0.1	)		24.4
Balance as of December 31, 2019	$	5,548.9		$	66.6		$	3.0		$	5,618.5

Major classes of amortizable intangible assets consist of the following (in millions):

	December 31,
	2019			2018
Expiration lists	$	4,246.0		$	3,379.4
Accumulated amortization - expiration lists		(2,004.3	)		(1,676.8	)
		2,241.7			1,702.6
Non-compete agreements		68.4			58.0
Accumulated amortization - non-compete agreements		(52.5	)		(48.5	)
		15.9			9.5
Trade names		91.8			86.0
Accumulated amortization - trade names		(30.7	)		(25.1	)
		61.1			60.9
Net amortizable assets	$	2,318.7		$	1,773.0

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

2020	$	366.5
2021		342.7
2022		316.6
2023		290.3
2024		254.0
Thereafter		748.6
Total	$	2,318.7