Supplemental Consolidated Statements of Income Information (Components of Other Operating Expense, Net) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Component Of Other Operating Income And Expense [Line Items]
(Gain) loss on purchase/sale of interests in subsidiaries and affiliates, net	[1]	¥ (29,595)	¥ (4,259)	¥ (31,778)
(Gain) loss on sale, disposal or impairment of assets, net	[2]	38,599	195,341	90,410
Other operating (income) expense, net		4,072	149,001	47,171
M3, Inc.
Component Of Other Operating Income And Expense [Line Items]
Gain on sale and issuance of M3 shares	[3]	(18)	(37,167)	(2)
United States Head Quarters
Component Of Other Operating Income And Expense [Line Items]
Gain on sale of building	[4]			(6,545)
Sony City Osaki
Component Of Other Operating Income And Expense [Line Items]
Gain on sale of building	[4]	¥ (4,914)	¥ (4,914)	¥ (4,914)

[1] Refer to Notes 24 and 25.

[2] Refer to Notes 9, 13, 19 and 25.

[3] Refer to Note 5.

[4] A portion of gain on sale and leaseback transactions is deferred and is amortized on a straight-line basis over the lease term.