XML 58 R170.htm IDEA: XBRL DOCUMENT  v2.3.0.11
Significant Concentrations of Credit Risk - Additional Information (Detail)
In Millions, unless otherwise specified
12 Months Ended
Mar. 31, 2011
Mar. 31, 2010
Mar. 31, 2011
Japan
USD ($)
Mar. 31, 2011
Japan
JPY (¥)
Mar. 31, 2010
Japan
JPY (¥)
Mar. 31, 2011
U.S.
USD ($)
Mar. 31, 2011
U.S.
JPY (¥)
Mar. 31, 2010
U.S.
JPY (¥)
Mar. 31, 2011
Real Estate Investment
Mar. 31, 2010
Real Estate Investment
Concentration Risk [Line Items]                    
Concentration of risk description No concentration with a single obligor exceeded 1% of consolidated total assets No concentration with a single obligor exceeded 1% of consolidated total assets                
Credit exposures on a geographic basis     $ 58,378 ¥ 4,854,000 ¥ 4,809,000 $ 12,040 ¥ 1,001,000 ¥ 387,000    
Concentration risk , percentage     76.00% 76.00% 85.00%       12.70% 14.40%