Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2021

Revenue From Contract With Customer [Abstract]

Summary of Unbilled Receivables, Contract Assets and Contract Liabilities from Contracts with Customers

Information about unbilled receivables, contract assets and contract liabilities from contracts with customers is as follows (in millions):

	December 31, 2021		December 31, 2020
Unbilled receivables	$	730.0	$	603.1
Deferred contract costs		129.7		102.0
Deferred revenue		579.6		541.3

Summary of Changes in Deferred Revenue Balances

Significant changes in the deferred revenue balances, which include foreign currency translation adjustments, during the period are as follows (in millions):

	Brokerage			Risk Management			Total
Deferred revenue at December 31, 2019	$	337.2		$	166.6		$	503.8
Incremental deferred revenue		282.7			91.3			374.0
Revenue recognized during the year ended December 31,    2020 included in deferred revenue at December 31, 2019		(283.1	)		(99.2	)		(382.3	)
Net change in collected billings/deposits received from customers		(0.7	)		26.3			25.6
Impact of changes in foreign exchange rates		8.7			1.6			10.3
Deferred revenue recognized from business acquisitions		9.9			—			9.9
Deferred revenue at December 31, 2020		354.7			186.6			541.3
Incremental deferred revenue		325.0			102.1			427.1
Revenue recognized during the year ended December 31,    2021 included in deferred revenue at December 31, 2020		(296.1	)		(103.5	)		(399.6	)
Net change in collected billings/deposits received from customers		(3.6	)		(0.7	)		(4.3	)
Impact of changes in foreign exchange rates		(3.7	)		(0.8	)		(4.5	)
Deferred revenue recognized from business acquisitions		19.6			—			19.6
Deferred revenue at December 31, 2021	$	395.9		$	183.7		$	579.6

Summary of Expected Revenue Related to Performance Obligations

The estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period is as follows (in millions):

	Brokerage		Risk Management		Total
2022	$	366.0	$	125.8	$	491.8
2023		26.0		27.4		53.4
2024		1.8		12.4		14.2
2025		1.0		6.5		7.5
2026		0.6		3.4		4.0
Thereafter		0.5		8.2		8.7
Total	$	395.9	$	183.7	$	579.6