Marketable securities and securities investments (Tables)

12 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Aggregate Cost, Gross Unrealized Gains and Losses and Fair Value Pertaining to Available-for-Sale Securities and Held-to-Maturity Securities

Marketable securities and securities investments, primarily included in the Financial Services segment, are comprised of debt and equity securities for which the aggregate cost, gross unrealized gains and losses and fair value pertaining to available-for-sale securities and held-to-maturity securities are as follows. Sony adopted ASU 2016-01 from April 1, 2018, and as a result, the available-for-sale classification is eliminated for equity securities as of March 31, 2019.

	Yen in millions
	March 31, 2018									March 31, 2019
	Cost		Gross unrealized gains		Gross unrealized losses			Fair value		Cost		Gross unrealized gains		Gross unrealized losses			Fair value
Available-for-sale:
Debt securities:
Japanese national government bonds		1,227,139		182,830		(359	)		1,409,610		1,422,620		220,989		(20	)		1,643,589
Japanese local government bonds		67,574		107		(112	)		67,569		67,461		70		(34	)		67,497
Japanese corporate bonds		199,880		9,844		(1,016	)		208,708		202,433		17,178		(223	)		219,388
Foreign government bonds		72,204		622		(3,287	)		69,539		153,429		8,669		(603	)		161,495
Foreign corporate bonds		365,457		1,649		(641	)		366,465		360,299		944		(376	)		360,867
Securitized products		99,349		1		(0	)		99,350		190,111		1		—			190,112
Other		—		—		—			—		2,286		2,402		—			4,688
		2,031,603		195,053		(5,415	)		2,221,241		2,398,639		250,253		(1,256	)		2,647,636
Equity securities		55,676		71,723		(776	)		126,623		—		—		—			—
Held-to-maturity securities:
Japanese national government bonds		5,892,868		1,635,036		(20,890	)		7,507,014		6,042,635		2,016,786		—			8,059,421
Japanese local government bonds		3,850		413		—			4,263		3,518		388		—			3,906
Japanese corporate bonds		345,818		16,912		(17,390	)		345,340		409,329		44,348		(5,845	)		447,832
Foreign government bonds		300,220		8,310		(18,570	)		289,960		386,392		18,609		(13,742	)		391,259
Foreign corporate bonds		198		13		—			211		198		11		—			209
		6,542,954		1,660,684		(56,850	)		8,146,788		6,842,072		2,080,142		(19,587	)		8,902,627
Total		8,630,233		1,927,460		(63,041	)		10,494,652		9,240,711		2,330,395		(20,843	)		11,550,263

Cost and Fair Value of Debt Securities Classified as Available-for-Sale Securities and Held-to-Maturity Securities by Contractual Maturity

The following table presents the cost and fair value of debt securities classified as available-for-sale securities and held-to-maturity securities by contractual maturity:

	Yen in millions
	March 31, 2019
	Available-for-sale securities				Held-to-maturity securities
	Cost		Fair value		Cost		Fair value
Due in one year or less		132,770		132,745		6,286		6,334
Due after one year through five years		455,624		462,682		37,281		40,085
Due after five years through ten years		476,261		552,287		393,787		453,310
Due after ten years		1,333,984		1,499,922		6,404,718		8,402,898
Total		2,398,639		2,647,636		6,842,072		8,902,627

Gross Unrealized Losses and Fair Value of Securities with Unrealized Losses, Aggregated by Investment Category and Length of Time in Continuous Unrealized Loss Position

The following tables present the gross unrealized losses on, and fair value of, Sony’s investment securities with unrealized losses, aggregated by investment category and the length of time that individual investment securities have been in a continuous unrealized loss position, at March 31, 2018 and 2019. Sony adopted ASU 2016-01 from April 1, 2018, and as a result, the available-for-sale classification is eliminated for equity securities as of March 31, 2019.

	Yen in millions
	March 31, 2018
	Less than 12 months					12 months or more					Total
	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
Available-for-sale:
Debt securities:
Japanese national government bonds		10,118		(11	)		32,836		(348	)		42,954		(359	)
Japanese local government bonds		9,324		(11	)		14,729		(101	)		24,053		(112	)
Japanese corporate bonds		11,046		(10	)		64,119		(1,006	)		75,165		(1,016	)
Foreign government bonds		40,156		(2,281	)		7,752		(1,006	)		47,908		(3,287	)
Foreign corporate bonds		34,840		(69	)		21,191		(572	)		56,031		(641	)
Securitized products		1,840		(0	)		315		(0	)		2,155		(0	)
		107,324		(2,382	)		140,942		(3,033	)		248,266		(5,415	)
Equity securities		13,859		(776	)		15		(0	)		13,874		(776	)
Held-to-maturity securities:
Japanese national government bonds		—		—			304,564		(20,890	)		304,564		(20,890	)
Japanese local government bonds		—		—			—		—			—		—
Japanese corporate bonds		—		—			174,815		(17,390	)		174,815		(17,390	)
Foreign government bonds		20,448		(704	)		134,230		(17,866	)		154,678		(18,570	)
Foreign corporate bonds		—		—			—		—			—		—
		20,448		(704	)		613,609		(56,146	)		634,057		(56,850	)
Total		141,631		(3,862	)		754,566		(59,179	)		896,197		(63,041	)

	Yen in millions
	March 31, 2019
	Less than 12 months					12 months or more					Total
	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
Available-for-sale:
Debt securities:
Japanese national government bonds		—		—			4,063		(20	)		4,063		(20	)
Japanese local government bonds		27,404		(29	)		4,872		(5	)		32,276		(34	)
Japanese corporate bonds		25,725		(21	)		19,925		(202	)		45,650		(223	)
Foreign government bonds		—		—			15,878		(603	)		15,878		(603	)
Foreign corporate bonds		50,281		(117	)		15,455		(259	)		65,736		(376	)
Securitized products		—		—			—		—			—		—
Other		—		—			—		—			—		—
		103,410		(167	)		60,193		(1,089	)		163,603		(1,256	)
Held-to-maturity securities:
Japanese national government bonds		—		—			—		—			—		—
Japanese local government bonds		—		—			—		—			—		—
Japanese corporate bonds		—		—			97,984		(5,845	)		97,984		(5,845	)
Foreign government bonds		—		—			151,229		(13,742	)		151,229		(13,742	)
Foreign corporate bonds		—		—			—		—			—		—
		—		—			249,213		(19,587	)		249,213		(19,587	)
Total		103,410		(167	)		309,406		(20,676	)		412,816		(20,843	)