Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	$ 138	$ 111
Cash payments	(151)	(74)
Restructuring charges	401	286
Other	(216)	(185)
Restructuring reserve ending balance	172	138
Layoff Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	96	59
Cash payments	(136)	(63)
Restructuring charges	215	201
Other	(40)	(101)
Restructuring reserve ending balance	135	96
Other Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve beginning balance	42	52
Cash payments	(15)	(11)
Restructuring charges	186	85
Other	(176)	(84)
Restructuring reserve ending balance	$ 37	$ 42