Revenue Recognition for Long-Term Contracts (Details) (JPY ¥) In Millions							12 Months Ended
Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2011 Notes Receivable [Member]	Mar. 31, 2010 Notes Receivable [Member]	Mar. 31, 2011 Accounts Receivable [Member]	Mar. 31, 2010 Accounts Receivable [Member]	Mar. 31, 2011 Minimum [Member]	Mar. 31, 2011 Maximum [Member]
Less than 1 year	¥ 12,794	¥ 8,121	¥ 241	¥ 176	¥ 12,553	¥ 7,945
1-2 years	789	236			789	236
Over 2 years
Completion of long-term contracts							two	three
Unbilled contracts receivable	¥ 0	¥ 0

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 3
-Subparagraph c(3)
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 11
-Section A
-Paragraph 4, 21

Name:	us-gaap_UnbilledContractsReceivable
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant