Restructuring - Charges and Spending Relating to Restructuring Activities by Program (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013
Restructuring Reserve [Roll Forward]
Expense	$ 612		$ 967	$ 1,359		$ 1,439
2013 Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				768
Expense	437		544	826		544
(Payments) receipts, net				(642)
Non-cash activity				(398)
Restructuring reserve, ending balance	554	[1]		554	[1]
Merger Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				737
Expense	175		423	533		841
(Payments) receipts, net				(408)
Non-cash activity				(263)
Restructuring reserve, ending balance	599	[1]		599	[1]
Separation Costs [Member]
Restructuring Reserve [Roll Forward]
Expense	315		742	491		970
Separation Costs [Member] | 2013 Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				745
Expense	310		501	387		501
(Payments) receipts, net				(596)
Non-cash activity				0
Restructuring reserve, ending balance	536	[1]		536	[1]
Separation Costs [Member] | Merger Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				725
Expense	5		241	104		435
(Payments) receipts, net				(237)
Non-cash activity				0
Restructuring reserve, ending balance	592	[1]		592	[1]
Accelerated Depreciation [Member]
Restructuring Reserve [Roll Forward]
Expense	221		94	714		210
Accelerated Depreciation [Member] | 2013 Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				0
Expense	125		43	441		43
(Payments) receipts, net				0
Non-cash activity				(441)
Restructuring reserve, ending balance	0	[1]		0	[1]
Accelerated Depreciation [Member] | Merger Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				0
Expense	96		51	273		165
(Payments) receipts, net				0
Non-cash activity				(273)
Restructuring reserve, ending balance	0	[1]		0	[1]
Other [Member]
Restructuring Reserve [Roll Forward]
Expense	76		131	154		259
Other [Member] | 2013 Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				23
Expense	2		0	(2)		0
(Payments) receipts, net				(46)
Non-cash activity				43
Restructuring reserve, ending balance	18	[1]		18	[1]
Other [Member] | Merger Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				12
Expense	74		131	156		241
(Payments) receipts, net				(171)
Non-cash activity				10
Restructuring reserve, ending balance	$ 7	[1]		$ 7	[1]

[1] The cash outlays associated with the 2013 Restructuring Program are expected to be substantially completed by the end of 2015. The non-manufacturing cash outlays associated with the Merger Restructuring Program were substantially completed by the end of 2013; the remaining cash outlays are expected to be substantially completed by 2016.