Summary of Potential Future Payments and Book Value Recorded as Guarantee Liabilities of Guarantee Contracts Outstanding (Detail) In Millions			12 Months Ended		12 Months Ended
Mar. 31, 2011 USD ($)	Mar. 31, 2011 JPY (¥)	Mar. 31, 2010 JPY (¥)	Mar. 31, 2011 Corporate loans USD ($)	Mar. 31, 2011 Corporate loans JPY (¥)	Mar. 31, 2010 Corporate loans JPY (¥)	Mar. 31, 2011 Transferred Loans USD ($)	Mar. 31, 2011 Transferred Loans JPY (¥)	Mar. 31, 2010 Transferred Loans JPY (¥)	Mar. 31, 2011 Housing Loans USD ($)	Mar. 31, 2011 Housing Loans JPY (¥)	Mar. 31, 2010 Housing Loans JPY (¥)	Mar. 31, 2011 Other USD ($)	Mar. 31, 2011 Other JPY (¥)	Mar. 31, 2010 Other JPY (¥)
Guarantor Obligations [Line Items]
Maturity of the longest contract (Years)				2018	2018	2017	2043	2043		2051	2051	2051	2018	2018	2012
Potential future payment	$ 5,971	¥ 496,452	¥ 340,249	$ 3,756	¥ 312,273	¥ 321,448	$ 2,008	¥ 166,936	¥ 0	$ 204	¥ 16,949	¥ 18,798	$ 3	¥ 294	¥ 3
Book value of guarantee liabilities	$ 79	¥ 6,533	¥ 5,631	$ 24	¥ 1,958	¥ 2,986	$ 27	¥ 2,218	¥ 0	$ 28	¥ 2,353	¥ 2,644	$ 0	¥ 4	¥ 1

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph c

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph b

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- Definition

Describe the approximate term of the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph a

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