Property, Plant and Equipment (Details)	Mar. 31, 2011 USD ($)	Mar. 31, 2011 JPY (¥)	Mar. 31, 2010 JPY (¥)	Mar. 31, 2009 JPY (¥)
Property, plant and equipment
Land	$ 1,149,506,000	¥ 95,409,000,000	¥ 92,355,000,000
Buildings	4,067,699,000	337,619,000,000	329,554,000,000
Machinery and equipment	8,367,554,000	694,507,000,000	710,511,000,000
Construction in progress	243,614,000	20,220,000,000	24,653,000,000
Total	13,828,373,000	1,147,755,000,000	1,157,073,000,000
Less: accumulated depreciation	(7,703,229,000)	(639,368,000,000)	(631,973,000,000)
Property, plant and equipment- less accumulated depreciation (Notes 1, 8, 9 and 16)	6,125,144,000	508,387,000,000	525,100,000,000	525,462,000,000
Property Plant And Equipment (Textuals) [Abstract]
Recognized damaged loss related to property, plant and equipment		¥ 1,217,000,000

Property Plant And Equipment.

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- Definition

Recognized damaged loss related to property, plant and equipment.

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- Definition

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5
-Subparagraph c

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 14
-Article 5

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- Definition

Carrying amount as of the balance sheet date of long-lived, depreciable assets that include building structures held for productive use including any addition, improvement, or renovation to the structure, such as interior masonry, interior flooring, electrical, and plumbing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

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Carrying amount at the balance sheet date of long-lived asset under construction that include construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

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Carrying amount as of the balance sheet date of real estate held for productive use. This excludes land held for sale.

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- Definition

Carrying amount as of the balance sheet date of long-lived, depreciable asset used in production process to produce goods and services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

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Carrying amount at the balance sheet date for long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, physical structures, machinery, vehicles, furniture, computer equipment, construction in progress, and similar items. Amount does not include depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

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Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, and production equipment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 13
-Subparagraph a
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 12
-Paragraph 5
-Subparagraph b, c

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 8
-Article 7

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