Contingencies: (Details) (USD $) In Millions, unless otherwise specified		0 Months Ended	3 Months Ended		0 Months Ended
	Mar. 31, 2014 countries	Oct. 12, 2012 Litigation in United Kingdom regarding defined benefit plans (C Plan)	Sep. 30, 2012 Litigation in United Kingdom regarding defined benefit plans (C Plan)	Mar. 31, 2014 Former IBM UK Defined Benefit Plan Participants IBM United Kingdom Limited claims	Jul. 25, 2013 Civil enforcement action with the SEC IBM Korea, LG IBM, IBM (China) Investment Company Limited and IBM Global Services (China) Co., Ltd.	Feb. 13, 2014 State of Indiana Pending Litigation	Jul. 18, 2012 State of Indiana Pending Litigation	Jul. 10, 2013 SCO Group Inc. claims	Apr. 16, 2014 Iusacell SA de C.V. Subsequent event Pending Litigation
Contingencies:
Clients presence in number of countries	175
Loss Contingencies
Amount of settlement to be (paid)/received						$ 50	$ 52
Claims pending				290
Additional pre-tax retirement-related obligation recorded			162
Retirement age of employee under the C Plan		60 years
Retirement age of employee under the C Plan before modifications		63 years
Period for which reports are to be submitted to SEC and court on certain matters, including those relating to compliance with the FCPA					2 years
Number of breaches of contract and copyright claims filed								10
Number of breaches of contract and copyright claims dismissed								7
Number of tortious interference claims dismissed								1
Damages sought, value									2,500
Income tax examination - Brazil, total potential liability	$ 720