Supplemental Expense Information - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Other Income and Expenses [Abstract]
Gains (losses) on sales of property, plant and equipment, net	¥ 12,039	¥ 339	¥ (486)

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2941-110230

Name:	us-gaap_GainLossOnDispositionOfAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration