Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	$ 132	$ 138	$ 111
Cash payments	(123)	(213)	(74)
Restructuring charges	532	453	286
Other	(291)	(246)	(185)
Restructuring reserve ending balance	250	132	138
Layoff Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	98	96	59
Cash payments	(111)	(191)	(63)
Restructuring charges	299	259	201
Other	(60)	(66)	(101)
Restructuring reserve ending balance	226	98	96
Other Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	34	42	52
Cash payments	(12)	(22)	(11)
Restructuring charges	233	194	85
Other	(231)	(180)	(84)
Restructuring reserve ending balance	$ 24	$ 34	$ 42