Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	$ 250	$ 132
Cash payments	(77)	(123)
Restructuring charges	45	532
Other	(20)	(291)
Restructuring reserve ending balance	198	250
Layoff Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	226	98
Cash payments	(67)	(111)
Restructuring charges	19	299
Other	(22)	(60)
Restructuring reserve ending balance	156	226
Other Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	24	34
Cash payments	(10)	(12)
Restructuring charges	26	233
Other	2	(231)
Restructuring reserve ending balance	$ 42	$ 24