Goodwill and Identifiable Intangible Assets - Summary of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Definite-lived identifiable intangible assets:
Gross Amount	$ 13,592	$ 11,930
Accumulated Amortization	(8,630)	(7,431)
Net Amount	4,962	4,499
Client relationships and backlog
Definite-lived identifiable intangible assets:
Gross Amount	6,653	5,690
Accumulated Amortization	(3,566)	(2,966)
Net Amount	3,087	2,724
Databases
Definite-lived identifiable intangible assets:
Gross Amount	1,892	1,773
Accumulated Amortization	(1,873)	(1,751)
Net Amount	19	22
Trademarks, trade names and other
Definite-lived identifiable intangible assets:
Gross Amount	570	539
Accumulated Amortization	(406)	(350)
Net Amount	164	189
Software and related assets
Definite-lived identifiable intangible assets:
Gross Amount	4,466	3,914
Accumulated Amortization	(2,782)	(2,358)
Net Amount	1,684	1,556
Non-compete agreements
Definite-lived identifiable intangible assets:
Gross Amount	11	14
Accumulated Amortization	(3)	(6)
Net Amount	$ 8	$ 8