Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2023

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, 2023		December 31, 2022
Unbilled receivables	$	1,093.7	$	910.9
Deferred contract costs		169.1		144.5
Deferred revenue		706.2		609.3

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, 2021	$	395.9		$	183.7		$	579.6
Incremental deferred revenue		342.3			103.2			445.5
Revenue recognized during the year ended December 31,    2022 included in deferred revenue at December 31, 2021		(326.3	)		(104.6	)		(430.9	)
Net change in collected billings/deposits received from customers		21.4			(7.0	)		14.4
Impact of changes in foreign exchange rates		(17.9	)		—			(17.9	)
Deferred revenue recognized from business acquisitions		18.6			—			18.6
Deferred revenue at December 31, 2022		434.0			175.3			609.3
Incremental deferred revenue		386.3			106.7			493.0
Revenue recognized during the year ended December 31,    2023 included in deferred revenue at December 31, 2022		(358.4	)		(103.6	)		(462.0	)
Net change in collected billings/deposits received from customers		18.8			(5.8	)		13.0
Impact of changes in foreign exchange rates		15.2			—			15.2
Deferred revenue recognized from business acquisitions		37.7			—			37.7
Deferred revenue at December 31, 2023	$	533.6		$	172.6		$	706.2

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
2024	$	498.4	$	42.7	$	541.1
2025		31.3		68.5		99.8
2026		1.9		28.1		30.0
2027		1.0		14.6		15.6
2028		0.5		7.9		8.4
Thereafter		0.5		10.8		11.3
Total	$	533.6	$	172.6	$	706.2