Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	$ 6,761	$ 6,693
Amortized intangibles, Accumulated Amortization	(3,771)	(3,590)
Trade names and trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	144	140
Amortized intangibles, Accumulated Amortization	(108)	(102)
Customer - related intangibles
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	3,147	3,145
Amortized intangibles, Accumulated Amortization	(1,725)	(1,604)
Covenants-not-to-compete
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	39	39
Amortized intangibles, Accumulated Amortization	(38)	(38)
Content database
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	168	167
Amortized intangibles, Accumulated Amortization	(37)	(26)
Computer software
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	3,083	3,029
Amortized intangibles, Accumulated Amortization	(1,726)	(1,694)
Patents and other
Finite And Indefinite Lived Intangible Assets [Line Items]
Amortized intangibles, Gross Amounts	180	173
Amortized intangibles, Accumulated Amortization	(137)	(126)
Trade names and trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Indefinite-lived intangibles, Gross Amounts	$ 1,921	$ 1,921