Debt Disclosure [Line Items]

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- Definition

Debt Instrument Conversion Trigger Stock Price Threshold

+ Details

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- Definition

Debt Instrument, Convertible, Conversion Price1

+ Details

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- Definition

Debt Instrument, Convertible, Number Of Share

+ Details

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- Definition

Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, (3) securities available-for-sale, and (4) non-marketable equity securities.

+ Details

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- Definition

The component of interest expense representing the noncash expenses charged against earnings in the period to allocate debt discount and premium, and the costs to issue debt and obtain financing over the related debt instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28

+ Details

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- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 21
-Paragraph 16, 20

+ Details

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number APB14-1
-Paragraph 31
-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 21
-Paragraph 16, 20

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

+ Details

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

+ Details

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- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 6
-Paragraph 9, 10, 11

+ Details

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Balance Type:	credit
Period Type:	instant

Short-Term and Long-Term Debt - Additional Information (Detail) In Millions, except Share data	12 Months Ended							12 Months Ended
	Mar. 31, 2011 USD ($)	Mar. 31, 2011 JPY (¥)	Mar. 31, 2010 JPY (¥)	Mar. 31, 2009 JPY (¥)	Mar. 31, 2011 Unsecured Convertible Bonds With Stock Acquisition Rights USD ($)	Mar. 31, 2011 Unsecured Convertible Bonds With Stock Acquisition Rights JPY (¥)	Dec. 31, 2008 Unsecured Convertible Bonds With Stock Acquisition Rights JPY (¥)	Mar. 31, 2011 Minimum Unsecured Bond With Stock Acquisition Rights USD ($)	Mar. 31, 2011 Maximum Unsecured Bond With Stock Acquisition Rights USD ($)	Mar. 31, 2011 Unsecured Bond With Stock Acquisition Rights USD ($)	Jun. 30, 2002 Unsecured Bond With Stock Acquisition Rights USD ($)	Mar. 31, 2011 Securities Pledged as Collateral USD ($)	Mar. 31, 2011 Securities Pledged as Collateral JPY (¥)
Debt Disclosure [Line Items]
Unsecured bond issued							¥ 150,000				$ 400
Unamortized Discount of debt											622
Debt instrument convertible into shares of common stock, shares					21,917,371	21,917,371				2,493,309
Debt instrument conversion Price					$ 82.29	¥ 6,842.70				$ 115.12
Debt instrument conversion trigger stock price threshold accretion								$ 126.63	$ 320.72
Net amortization expenses of bond premiums and discounts, deferred issuance costs of bonds and medium-term notes	48	3,996	4,022	3,551
Total committed credit lines	5,585	464,432	426,729
Available credit lines	4,936	410,447	385,892
Long-term committed credit lines	1,287	107,010	162,337
Investment in securities pledged for primarily collateral deposits	$ 14,136	¥ 1,175,381	¥ 1,104,158									$ 705	¥ 58,607