Segment and Geographic Information 3 (Details) (Restructuring Activity Fiscal Plan 2012 [Member], Severance [Member], USD $) In Millions	3 Months Ended	6 Months Ended
Sep. 30, 2011 Mainframe Solutions [Member]	Sep. 30, 2011 Enterprise Solutions [Member]	Sep. 30, 2011 Services [Member]	Sep. 30, 2011
Segment Reporting Information [Line Items]
Severance costs	$ 23	$ 20	$ 1	$ 44

Reserve increase representing the amount charged against earnings in the period for a specified incurred and estimated type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 146

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Name:	us-gaap_RestructuringReservePeriodExpense
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration