Intangible Assets Including Goodwill: (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2012	Dec. 31, 2011
Changes in Goodwill Balances
Beginning Balance	$ 26,213	$ 25,136
Goodwill Additions	1,067	1,291
Purchase Price Adjustments	2	2
Divestitures		(13)
Foreign Currency Translation and Other Adjustments	186	(203)
Ending Balance	27,468	26,213
Global Business Services
Changes in Goodwill Balances
Beginning Balance	4,313	4,329
Goodwill Additions		14
Purchase Price Adjustments	0	0
Divestitures		(10)
Foreign Currency Translation and Other Adjustments	55	(20)
Ending Balance	4,368	4,313
Global Technology Services
Changes in Goodwill Balances
Beginning Balance	2,646	2,704
Purchase Price Adjustments		(1)
Divestitures		(2)
Foreign Currency Translation and Other Adjustments	15	(55)
Ending Balance	2,661	2,646
Software.
Changes in Goodwill Balances
Beginning Balance	18,121	16,963
Goodwill Additions	846	1,277
Purchase Price Adjustments	2	10
Divestitures		(2)
Foreign Currency Translation and Other Adjustments	110	(127)
Ending Balance	19,079	18,121
Systems and Technology
Changes in Goodwill Balances
Beginning Balance	1,133	1,139
Goodwill Additions	221
Purchase Price Adjustments	0	(6)
Foreign Currency Translation and Other Adjustments	6	0
Ending Balance	$ 1,360	$ 1,133

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

+ References+ Details

- Definition

The increase (decrease) in the recorded value of goodwill for foreign currency translation adjustments and purchase accounting adjustments needed to revise the carrying amount of goodwill to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

Write-off of the carrying amount of goodwill associated with all or a portion of a reporting unit that is sold in the period.

+ References+ Details