Retirement and Pension Plans (Schedule of Estimated Prior Service Benefit and Actuarial (Loss)) (Details) (JPY ¥) In Millions	12 Months Ended
Mar. 31, 2011
Retirement and Pension Plans
Prior service benefit	¥ (808)
Actuarial loss	¥ 693

The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph s

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph d

Name:	us-gaap_DefinedBenefitPlanAmortizationOfNetGainsLosses
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration