Income Taxes - Reconciliation of Beginning and Ending Amount of Gross Unrecognized Income Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Beginning balance	$ 30	$ 41	$ 55
IMS Health balance as of Merger	37
Additions based on tax positions related to the current year	3	2	3
Additions for income tax positions of prior years	7	9	1
Impact of changes in exchange rates	(3)	(1)
Reductions for income tax positions of prior years	(1)	(2)	(6)
Reductions due to the lapse of the applicable statute of limitations	(9)	(19)	(12)
Ending balance	$ 64	$ 30	$ 41