Summary of Significant Accounting Policies (Details) (JPY ¥) In Millions, except Share data, unless otherwise specified	12 Months Ended
Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Total assets of the VIE	¥ 199	¥ 219
Time deposits, total	28,907	24,230	4,022
Restricted cash	¥ 925	¥ 573	¥ 566
Net actuarial gain and losses	20.00%
Long term contracts for revenue recognition	2.20%	2.10%	1.90%
Deferred tax benefit	50.00%
Weighted average number of shares outstanding, basic	1,271,778,025	1,271,985,454	1,275,574,702
Potentially dilutive shares outstanding	0	0	0
Minimum [Member]
Defined benefit plan amortization of gains losses in percentage	10.00%
Maximum [Member]
Defined benefit plan amortization of gains losses in percentage	20.00%
Japan [Member]
Number of plants	20
United States [Member]
Number of plants	12
Building [Member]
Property, plant and equipment, useful life, minimum	10
Property, plant and equipment, useful life, maximum	50
Machinery and Equipment [Member]
Property, plant and equipment, useful life, minimum	2
Property, plant and equipment, useful life, maximum	14

The percentage which the Company consider more likely than not in determining the possibility of realization.

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The percentage of net actuarial gain and losses (defined above) in excess of the larger of the projected benefit obligation or plan assets, which is amortized over the average participants' remaining service period.

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The portion of the revenues recognized on long term contracts out of the total revenues of the company in each disclosed year.

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Number Of Plants

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- Definition

Percentage of excess recognized net actuarial gains and losses by projected benefit obligation or plan assets.

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 13, 14

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph c

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- Definition

The maximum useful life of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include land and improvements, buildings, and production equipment.

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The minimum useful life of long lived, physical assets used in the normal conduct of business and not intended for resale. Examples include land and improvements, buildings, and production equipment.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Audit and Accounting Guide (AAG)
-Number AAG-BRD
-Chapter 4
-Paragraph 80
-Subparagraph Exhibit 4-8, 3
-IssueDate 2006-05-01

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- Definition

The aggregate amount of time deposits, including certificates of deposits, individual retirement accounts and open accounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 12
-Article 9

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- Definition

The carrying amount of the variable interest entity's assets consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities. A VIE often holds financial assets, including loans or receivables, real estate or other property. A VIE may be essentially passive or it may engage in research and development or other activities on behalf of another company.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 26
-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS140-4 and FIN46(R)-8
-Paragraph 9
-Subparagraph c(5), c(6)

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 23
-Subparagraph a

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS140-4 and FIN46(R)-8
-Paragraph C5
-Subparagraph a

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 23
-Subparagraph b

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 24
-Subparagraph b

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS140-4 and FIN46(R)-8
-Paragraph C8
-Subparagraph b

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- Definition

Number of [basic] shares, after adjustment for contingently issuable shares and other shares not deemed outstanding, determined by relating the portion of time within a reporting period that common shares have been outstanding to the total time in that period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph a

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 8

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