Quarterly Financial Results and Market for Company's Stock (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Quarterly Financial Information [Line Items]
Business optimization, acquisition, collaboration arrangements and other charges	$ 17	$ 191		$ 29	$ 47	$ 43	$ 78	$ 46
Business optimization, acquisition, collaboration arrangements and other benefits			$ 5