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 |