Retirement Benefits - Expense (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Amortization Categories [Abstract]
(Gain)/Loss from curtailment and settlements		$ (29)	$ (4)
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	467	376	343
Interest cost	2,374	2,530	2,698
Expected return on assets	(3,028)	(3,172)	(3,288)
Defined Benefit Plan Amortization Categories [Abstract]
Prior service costs/(credits)	343	370	374
(Gains)/Losses and Other	186	12	8
Separation programs	9	6	12
(Gain)/Loss from curtailment and settlements			0
Net expense/(income)	351	122	147
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	327	314	293
Interest cost	1,227	1,249	1,253
Expected return on assets	(1,404)	(1,337)	(1,309)
Defined Benefit Plan Amortization Categories [Abstract]
Prior service costs/(credits)	72	75	83
(Gains)/Losses and Other	333	246	158
Separation programs	138	26	176
(Gain)/Loss from curtailment and settlements	111		47
Net expense/(income)	804	573	701
Worldwide OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	63	54	408
Interest cost	327	338	899
Expected return on assets			(130)
Defined Benefit Plan Amortization Categories [Abstract]
Prior service costs/(credits)	(612)	(617)	(913)
(Gains)/Losses and Other	94	96	82
Separation programs	10	1	2
(Gain)/Loss from curtailment and settlements	(26)	(30)	244
Net expense/(income)	(144)	(158)	592
Automotive [Member]
Defined Benefit Plan Amortization Categories [Abstract]
(Gain)/Loss from curtailment and settlements		(29)	(4)
Financial Services [Member]
Defined Benefit Plan Amortization Categories [Abstract]
(Gain)/Loss from curtailment and settlements		0	0
Scenario, Previously Reported [Member] | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 290