Intangible Assets Including Goodwill: (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Changes in Goodwill Balances
Beginning Balance	$ 31,184	$ 29,247
Goodwill Additions	239	2,246
Purchase Price Adjustments	0	61
Divestitures	(52)	(7)
Foreign Currency Translation and Other Adjustments	(158)	(363)
Ending Balance	31,214	31,184
Goodwill impairment losses	0	0
Goodwill accumulated impairment losses	0	0
Global Business Services
Changes in Goodwill Balances
Beginning Balance	4,334	4,357
Purchase Price Adjustments		0
Divestitures		(3)
Foreign Currency Translation and Other Adjustments	4	(21)
Ending Balance	4,337	4,334
Global Technology Services
Changes in Goodwill Balances
Beginning Balance	4,129	2,916
Goodwill Additions		1,246
Purchase Price Adjustments		17
Divestitures	(52)
Foreign Currency Translation and Other Adjustments	16	(50)
Ending Balance	4,094	4,129
Software
Changes in Goodwill Balances
Beginning Balance	21,121	20,405
Goodwill Additions	239	987
Purchase Price Adjustments	0	11
Divestitures		(4)
Foreign Currency Translation and Other Adjustments	(170)	(279)
Ending Balance	21,190	21,121
Systems and Technology
Changes in Goodwill Balances
Beginning Balance	1,601	1,568
Goodwill Additions		13
Purchase Price Adjustments		33
Foreign Currency Translation and Other Adjustments	(8)	(14)
Ending Balance	$ 1,593	$ 1,601