Derivative instruments and hedging activities (Tables)

12 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Estimated Fair Values by Fair Value Hierarchy Level of Certain Financial Instruments not Reported at Fair Value

The estimated fair values of Sony’s outstanding derivative instruments are summarized as follows:

Derivatives designated as hedging instruments	Yen in millions
	Balance sheet location	Fair value				Balance sheet location	Fair value
		March 31					March 31
	Asset derivatives	2017		2018		Liability derivatives	2017		2018
Interest rate contracts	Prepaid expenses and other current assets		43		12	Current liabilities: Other		497		160
Interest rate contracts	Other assets: Other		95		286	Liabilities: Other		13,713		10,281
Foreign exchange contracts	Prepaid expenses and other current assets		—		48	Current liabilities: Other		31		1,535
			138		346			14,241		11,976
Derivatives not designated as hedging instruments	Yen in millions
	Balance sheet location	Fair value				Balance sheet location	Fair value
		March 31					March 31
	Asset derivatives	2017		2018		Liability derivatives	2017		2018
Interest rate contracts	Prepaid expenses and other current assets		3		12	Current liabilities: Other		221		299
Interest rate contracts	Other assets: Other		1,599		1,871	Liabilities: Other		4,374		3,612
Foreign exchange contracts	Prepaid expenses and other current assets		24,382		34,737	Current liabilities: Other		14,475		17,149
Foreign exchange contracts	Other assets: Other		157		366	Liabilities: Other		620		1,281
Equity contracts	Prepaid expenses and other current assets		981		2,194	Current liabilities: Other		519		1,407
			27,122		39,180			20,209		23,748
Total derivatives			27,260		39,526			34,450		35,724

Effects of Derivative Instruments on Consolidated Statements of Income

Presented below are the effects of derivative instruments on the consolidated statements of income for the fiscal years ended March 31, 2016, 2017 and 2018.

Derivatives under fair value hedging relationships	Yen in millions
	Location of gain or (loss) recognized in income on derivative	Amount of gain or (loss) recognized in income on derivative
		Fiscal year ended March 31
		2016			2017			2018
Interest rate contracts	Financial services revenue		(8,300	)		1,967			(52	)
Foreign exchange contracts	Foreign exchange loss, net		3			(31	)		—
Total			(8,297	)		1,936			(52	)
	Yen in millions
Derivatives under cash flow hedging relationships	Location of gain or (loss) recognized in income on derivative	Fiscal year ended March 31
		2016			2017			2018
		Amount of gain or (loss) recognized in OCI on derivative
Foreign exchange contracts	—		1,914			6,715			(2,295	)
Total			1,914			6,715			(2,295	)
		Amount of gain or (loss) reclassified from accumulated OCI into income (effective portion)
Foreign exchange contracts	Foreign exchange loss, net		(8	)		—			—
Foreign exchange contracts	Cost of sales		(3,104	)		(5,583	)		1,111
Total			(3,112	)		(5,583	)		1,111

Derivatives not designated as hedging instruments	Yen in millions
	Location of gain or (loss) recognized in income on derivative	Amount of gain or (loss) recognized in income on derivative
		Fiscal year ended March 31
		2016			2017			2018
Interest rate contracts	Financial services revenue		(5,499	)		(935	)		(1,544	)
Foreign exchange contracts	Financial services revenue		4,166			(5,365	)		2,013
Foreign exchange contracts	Foreign exchange loss, net		(14,501	)		12,339			21,370
Equity contracts	Financial services revenue		3,267			(18,597	)		(11,665	)
Total			(12,567	)		(12,558	)		10,174

Summary of Derivatives Additional Information Including Notional Amounts

The following table summarizes additional information, including notional amounts, for each type of derivative:

	Yen in millions
	March 31, 2017					March 31, 2018
	Notional amount		Fair value			Notional amount		Fair value
Foreign exchange contracts:
Foreign exchange forward contracts		1,062,933		3,011			1,105,393		7,071
Currency option contracts purchased		212		1			206		1
Currency option contracts written		214		(1	)		156		(1	)
Currency swap agreements		1,439,395		4,074			1,230,254		4,613
Other currency contracts		64,944		2,328			84,623		3,502
Interest rate contracts:
Interest rate swap agreements		415,719		(17,065	)		398,291		(12,171	)
Equity contracts:
Equity future contracts		96,016		462			106,876		787

Summary of Effects of Offsetting Derivative Assets, Derivative Liabilities, Financial Assets and Financial Liabilities

Presented below are the effects of offsetting derivative assets, derivative liabilities, financial assets and financial liabilities as of March 31, 2017 and 2018.

	Yen in millions
	As of March 31, 2017
	Gross amounts presented in the consolidated balance sheet		Gross amounts not offset in the consolidated balance sheet that are subject to master netting agreements
			Financial instruments		Cash collateral		Net amounts
Derivative assets subject to master netting agreements		11,554		6,584		277		4,693
Derivative assets not subject to master netting agreements		15,706						15,706
Total assets		27,260		6,584		277		20,399
Derivative liabilities subject to master netting agreements		33,261		6,644		18,631		7,986
Derivative liabilities not subject to master netting agreements		1,189						1,189
Repurchase, securities lending and similar arrangements		310,609		309,987		—		622
Total liabilities		345,059		316,631		18,631		9,797
	Yen in millions
	As of March 31, 2018
	Gross amounts presented in the consolidated balance sheet		Gross amounts not offset in the consolidated balance sheet that are subject to master netting agreements
			Financial instruments		Cash collateral		Net amounts
Derivative assets subject to master netting agreements		15,404		7,724		449		7,231
Derivative assets not subject to master netting agreements		24,122						24,122
Total assets		39,526		7,724		449		31,353
Derivative liabilities subject to master netting agreements		34,455		8,326		14,334		11,795
Derivative liabilities not subject to master netting agreements		1,269						1,269
Repurchase, securities lending and similar arrangements		335,586		334,246		—		1,340
Total liabilities		371,310		342,572		14,334		14,404