Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	$ 6,408	$ 6,310
Amortized intangibles, Accumulated Amortization	(3,523)	(3,350)
Trade names and trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	144	144
Amortized intangibles, Accumulated Amortization	(110)	(109)
Customer - related intangibles
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	3,144	3,153
Amortized intangibles, Accumulated Amortization	(1,809)	(1,764)
Covenants-not-to-compete
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	37	37
Amortized intangibles, Accumulated Amortization	(36)	(36)
Content database
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	168	168
Amortized intangibles, Accumulated Amortization	(43)	(40)
Computer software
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	2,732	2,626
Amortized intangibles, Accumulated Amortization	(1,381)	(1,260)
Patents and other
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	183	182
Amortized intangibles, Accumulated Amortization	(144)	(141)
Trade names and trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Indefinite-lived intangibles, Gross Amounts	$ 1,921	$ 1,921