Retirement-Related Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Retirement-related plans cost
Defined benefit and contribution pension plan - cost	$ 674	$ 532
Nonpension postretirement plans - cost	80	84
Total	754	616
Year-to-year percent change, defined benefit and contribution pension plans cost	26.70%
Year-to-year percent change, Nonpension postretirement plans cost	(5.10%)
Year-to-year percent change, total	22.40%
Proceeds from Medicare Prescription Drug Improvement and Modernization Act of 2003	6.1	16.5
Defined Benefit Pension Plans | U.S. Plan(s)
Retirement-related plans cost
Interest cost	496	550
Expected return on plan assets	(995)	(1,011)
Amortization of prior service costs/(credits)	2	2
Recognized actuarial losses	451	336
Total net periodic pension (income)/cost of defined benefit plans	(46)	(122)
Cost of defined contribution plans	206	264
Defined benefit and contribution pension plan - cost	160	142
Defined Benefit Pension Plans | Non-U.S. Plans
Retirement-related plans cost
Service cost	131	112
Interest cost	382	450
Expected return on plan assets	(554)	(580)
Amortization of prior service costs/(credits)	(31)	(39)
Recognized actuarial losses	404	259
Curtailments and settlements	0	1
Multi-employer plan/other costs	30	23
Total net periodic pension (income)/cost of defined benefit plans	363	227
Cost of defined contribution plans	151	163
Defined benefit and contribution pension plan - cost	514	390
Year-to-date contributions to non-U.S. defined benefit plans	147
Defined Benefit Pension Plans | Non-U.S. Plans | Multi-employer Plans
Retirement-related plans cost
Expected current year contributions to non-U.S. defined benefit plans	700
Nonpension Postretirement Plans | U.S. Plan(s)
Retirement-related plans cost
Service cost	9	9
Interest cost	42	49
Expected return on plan assets	0
Recognized actuarial losses	8	6
Nonpension postretirement plans - cost	58	64
Nonpension Postretirement Plans | Non-U.S. Plans
Retirement-related plans cost
Service cost	3	2
Interest cost	16	17
Expected return on plan assets	(2)	(3)
Amortization of prior service costs/(credits)	(1)	(1)
Recognized actuarial losses	6	4
Nonpension postretirement plans - cost	$ 22	$ 20