Other Investments (Schedule Of Cost, Fair Value, And Gross Unrealized Holding Gains And Losses For Securities) (Detail) (JPY ¥) In Millions, unless otherwise specified	Mar. 31, 2012	Mar. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cost	¥ 38,431	¥ 40,408
Fair Value	92,399	90,473
Gross Unrealized Holding Gains	53,978	51,196
Gross Unrealized Holding Losses	10	1,131
Equity Securities Of Financial Institutions
Schedule of Available-for-sale Securities [Line Items]
Cost	23,656	25,525
Fair Value	34,339	34,839
Gross Unrealized Holding Gains	10,685	10,403
Gross Unrealized Holding Losses	2	1,089
Other Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	14,775	14,883
Fair Value	58,060	55,634
Gross Unrealized Holding Gains	43,293	40,793
Gross Unrealized Holding Losses	¥ 8	¥ 42

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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