XML 50 R158.htm IDEA: XBRL DOCUMENT  v2.3.0.11
Life Insurance Operations - Additional Information (Detail)
In Millions
12 Months Ended
Mar. 31, 2011
USD ($)
Mar. 31, 2011
JPY (¥)
Mar. 31, 2010
JPY (¥)
Mar. 31, 2009
JPY (¥)
Schedule of Investment Income, Reported Amounts, by Category [Line Items]        
Amortization of policy acquisition costs charged to income $ 116 ¥ 9,661 ¥ 10,994 ¥ 11,771