Acquisitions/Divestitures (Divestitures) (Details 4) - Microelectronics business - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jul. 01, 2015	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2015
Discontinued Operations
Description of continuing involvement after transaction				The transaction includes a 10-year exclusive manufacturing sourcing agreement in which GLOBALFOUNDRIES will provide server processor semiconductor technology for use in IBM Systems. The agreement provides the company with capacity and market-based pricing for current semiconductor nodes in production and progression to nodes in the future for both development and production needs. As part of the transaction, the company will provide GLOBALFOUNDRIES with certain transition services, including IT, supply chain, packaging and test services and lab services. The initial term for these transition services is one to three years, with GLOBALFOUNDRIES having the ability to renew.
Discontinued operation, period of exclusive manufacturing agreement after disposal				10 years
Name of the reportable segment				Systems Hardware
Pre-tax charge related to expected sale		$ 37	$ 4,700	$ 51
Impairment of long-lived assets			2,400
Total cash consideration expected to be transferred to acquiring company			1,500
Other related costs			$ 800
Cumulative pre-tax gain/(loss) on sale of business				$ 4,800
Net cash transferred at closing date	$ 472
Cash consideration payable at closing date	$ 750
Period of time over which cash consideration is expected to be transferred				3 years
Minimum
Discontinued Operations
Discontinued operation, period of continuing involvement after disposal				1 year
Maximum
Discontinued Operations
Discontinued operation, period of continuing involvement after disposal				3 years