Retirement And Pension Plans (Schedule Of Amounts Recognized In Other Comprehensive Income (Loss), Before Tax) (Detail) (JPY ¥) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Retirement And Pension Plans [Abstract]
Actuarial gain (loss) recognized in other comprehensive income	¥ 4,317	¥ (12,529)	¥ (4,602)
Reclassification adjustment for prior service benefit realized in net income	(808)	(808)	(808)
Reclassification adjustment for actuarial loss realized in net income	6,177	693	472
Net recognized in other comprehensive income (loss), before tax	¥ 9,686	¥ (12,644)	¥ (4,938)

The amount of gains or losses recognized in net periodic benefit cost.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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-Section 50

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- Definition

The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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-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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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- Definition

Before tax amount, net of reclassifications, of pension and other postretirement benefit plans (gain) loss included in accumulated other comprehensive income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

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-Section 45

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Before tax amount of the (increase) decrease in the value of the projected benefit obligation and the increase (decrease) in the value of the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption that has not been recognized in net periodic benefit cost.

+ References

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

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