Restructuring initiatives - Additional Information (Detail) (JPY ¥) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Group-wide restructuring initiatives primarily focusing on the Wholesale Division [Member]
Restructuring Initiatives [Line Items]
Employee termination costs	¥ 372	¥ 12,397
Employee termination costs in total	12,769
Restructuring costs settled	5,710
Restructuring charges recorded in the liability	2,148	7,083
Further restructuring initiative focusing on the Wholesale Division [Member]
Restructuring Initiatives [Line Items]
Employee termination costs	15,588
Restructuring costs settled	8,165
Restructuring charges recorded in the liability	¥ 5,741

Amount of cash paid in the period to fully or partially settle a specified, previously accrued type of restructuring cost.

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The charge against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

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