Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Goodwill by Reporting Segment (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Balance as of December 31, 2018	$ 2,654
Changes in preliminary purchase price allocation for prior acquisitions	61	[1]
Currency translation adjustments	(34)
Balance as of March 31, 2019	$ 2,681	[2]

[1] See Note 3, Business Combination for further discussion.

[2] At March 31, 2019, we had approximately $2.2 billion of cumulative impairment charges recorded in conjunction with our impairment analysis performed during the fourth quarter of 2018, as further described in the 2018 Form 10-K.