Total Defined Contribution Expenses (Detail) (JPY ¥) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Japanese plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expenses	¥ 3,729	¥ 464	¥ 9
Foreign plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expenses	¥ 13,070	¥ 6,726	¥ 4,350

Amount of administrative expenses incurred by a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanAdministrativeExpenses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration