Contracts with Customers - Summary of Changes in Deferred Revenue Balances (Detail) $ in Millions	9 Months Ended
Sep. 30, 2026 USD ($)
Change in Contract with Customer, Liability [Roll Forward]
Deferred revenue beginning balance	$ 892
Incremental deferred revenue	568
Revenue recognized during the nine-month period ended September 30, 2026 included in deferred revenue at December 31, 2025	(491)
Net change in collected billings/deposits received from customers	49
Impact of change in foreign exchange rates	(1)
Deferred revenue recognized from business acquisitions	11
Deferred revenue ending balance	1,028
Brokerage
Change in Contract with Customer, Liability [Roll Forward]
Deferred revenue beginning balance	693
Incremental deferred revenue	471
Revenue recognized during the nine-month period ended September 30, 2026 included in deferred revenue at December 31, 2025	(405)
Net change in collected billings/deposits received from customers	40
Impact of change in foreign exchange rates	(2)
Deferred revenue recognized from business acquisitions	11
Deferred revenue ending balance	808
Risk Management
Change in Contract with Customer, Liability [Roll Forward]
Deferred revenue beginning balance	199
Incremental deferred revenue	97
Revenue recognized during the nine-month period ended September 30, 2026 included in deferred revenue at December 31, 2025	(86)
Net change in collected billings/deposits received from customers	9
Impact of change in foreign exchange rates	1
Deferred revenue recognized from business acquisitions	0
Deferred revenue ending balance	$ 220

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Contract with customer impact of change in foreign exchange rates.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-11

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Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration from customer has been received or is due, from business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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