| **Restructuring And Other Charges (Tables)**                   | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| **Restructuring Charges [Abstract]**                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| Restructuring And Other Restructuring Plan-Related Information | Restructuring and other restructuring plan-related information as of December 31, 2012 was as follows (in millions):  Fiscal 2013Restructuring Fiscal 2011Restructuring OtherRestructurings and Reorganization   Workforce Facilities-related Other Workforce Other Facilities-related Other TotalBalances as of March 31, 2011$— $— $— $3 $101 $8 $5 $117Charges to operations— — — (1) 21 (12) 8 16Charges settled in cash— — — (2) (47) 7 (13) (55)Balances as of March 31, 2012— — — — 75 3 — 78Charges to operations10 4 9 — 5 (1) — 27Charges settled in cash(10) — (1) — (16) (1) — (28)Changes settled in non-cash— (1) (7) — — 1 — (7)Balances as of December 31, 2012$— $3 $1 $— $64 $2 $— $70 |

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| - Definition
Tabular disclosure of an entity's restructuring reserve that occurred during the period associated with the exit from or disposal of business activities or restructurings for each major type of cost. This element may also include a description of any reversal and other adjustment made during the period to the amount of an accrued liability for restructuring activities. This element may be used to encapsulate the roll forward presentations of an entity's restructuring reserve by type of cost and in total, and explanation of changes that occurred in the period.
+ References
Reference 1: 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=d3e17939-110869Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(b)(2)) -URI http://asc.fasb.org/extlink&oid=6394695&loc=d3e140904-122747Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 146 -Paragraph 20 -Subparagraph b(2) -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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