Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	$ 250	$ 132
Cash payments	(165)	(123)
Restructuring charges	106	532
Other	(59)	(291)
Restructuring reserve ending balance	132	250
Layoff Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	226	98
Cash payments	(132)	(111)
Restructuring charges	54	299
Other	(56)	(60)
Restructuring reserve ending balance	92	226
Other Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	24	34
Cash payments	(33)	(12)
Restructuring charges	52	233
Other	(3)	(231)
Restructuring reserve ending balance	$ 40	$ 24