Accumulated Other Comprehensive Income/(Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Foreign currency transaction
Other comprehensive income/(loss), net of tax	$ (433)	$ (778)	$ (800)	$ (255)
Derivative instruments
Other comprehensive income/(loss), net of tax	189	(89)	286	(152)
Pension and other postretirement benefits
Other comprehensive income/(loss), net of tax	940	253	1,531	213
Total AOCI ending balance	(21,837)		(21,837)		(22,854)
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			212
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Portion Attributable to Parent [Abstract]
Net gain/(loss) on derivative instruments, tax			94	(118)
Reclassifications to net income, tax			40	51
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent [Abstract]
Net gain/(loss) arising during period, tax			236	0
Amortization of prior service cost included in net income, tax			(15)	(54)
Amortization of gain/(loss) included in net income, tax			355	151
Parent [Member]
Foreign currency transaction
Beginning balance			(1,241)	(1,383)
Net gain/(loss) on foreign currency translation			(791)	(255)
Reclassifications to net income			(9)	0
Other comprehensive income/(loss), net of tax			(800)	(255)
Ending balance	(2,041)	(1,638)	(2,041)	(1,638)
Derivative instruments
Beginning balance			(175)	(181)
Net gain/(loss) on derivative instruments			201	(251)
Reclassifications to net income			85	99
Other comprehensive income/(loss), net of tax			286	(152)
Ending balance	111	(333)	111	(333)
Pension and other postretirement benefits
Beginning balance			(21,438)	(17,170)
Prior service cost arising during the period			0	0
Net gain/(loss) arising during the period			458	0
Amortization of prior service cost included in net income			(7)	(82)
Amortization of (gain)/loss included in net income			752	331
Translation impact on non-U.S. plans			328	(36)
Other comprehensive income/(loss), net of tax			1,531	213
Ending balance	(19,907)	(16,957)	(19,907)	(16,957)
Total AOCI ending balance	$ (21,837)	$ (18,928)	$ (21,837)	$ (18,928)