Securitizations and Variable Interest Entities - Classification of Consolidated VIEs' Assets and Liabilities (Parenthetical) (Detail) ¥ in Billions	Mar. 31, 2014 JPY (¥)
Variable Interest Entity, primary beneficiary [Member]
Variable Interest Entity [Line Items]
Aircraft purchase deposits	¥ 5

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.

No definition available.

Name:	us-gaap_VariableInterestEntityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration