Marketable Securities and Securities Investments (Tables)

12 Months Ended

Mar. 31, 2012

Debt and Equity Securities of 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, mainly included in the Financial Services segment, are comprised of debt and equity securities of 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:

	Yen in millions
	March 31, 2011									March 31, 2012
	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		1,124,704		24,032		(4,971	)		1,143,765		1,036,946		55,384		(879	)		1,091,451
Japanese local government bonds		22,845		184		(64	)		22,965		33,513		163		(1	)		33,675
Japanese corporate bonds		332,567		1,511		(440	)		333,638		293,885		1,489		(224	)		295,150
Foreign corporate bonds		332,316		4,872		(11,367	)		325,821		377,609		4,705		(7,063	)		375,251
Other		8,241		109		(118	)		8,232		22,383		1,548		(6	)		23,925
		1,820,673		30,708		(16,960	)		1,834,421		1,764,336		63,289		(8,173	)		1,819,452
Equity securities		80,983		63,822		(3,316	)		141,489		60,694		53,016		(1,513	)		112,197
Held-to-maturity Securities:
Japanese national government bonds		2,902,342		22,420		(48,149	)		2,876,613		3,404,069		157,740		(4,499	)		3,557,310
Japanese local government bonds		18,912		218		(2	)		19,128		12,592		277		—			12,869
Japanese corporate bonds		32,349		158		(67	)		32,440		31,379		1,501		—			32,880
Foreign corporate bonds		47,330		13		(3	)		47,340		46,441		10		—			46,451
		3,000,933		22,809		(48,221	)		2,975,521		3,494,481		159,528		(4,499	)		3,649,510
Total		4,902,589		117,339		(68,497	)		4,951,431		5,319,511		275,833		(14,185	)		5,581,159

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, 2012
	Available-for-sale securities				Held-to-maturity securities
	Cost		Fair Value		Cost		Fair Value
Due in one year or less		230,037		223,870		23,552		23,625
Due after one year through five years		505,497		510,183		18,280		18,559
Due after five year through ten years		210,411		215,180		27,225		28,219
Due after ten years		818,391		870,219		3,425,424		3,579,107
Total		1,764,336		1,819,452		3,494,481		3,649,510

Gross Unrealized Losses and Fair Value of Securities with Unrealized Losses, Aggregated by Investment Category and Length of Time of 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, 2011 and 2012.

	Yen in millions
	March 31, 2011
	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		223,686		(3,230	)		54,477		(1,741	)		278,163		(4,971	)
Japanese local government bonds		12,434		(64	)		—		—			12,434		(64	)
Japanese corporate bonds		130,318		(440	)		—		—			130,318		(440	)
Foreign corporate bonds		126,184		(7,183	)		30,277		(4,184	)		156,461		(11,367	)
Other		3,182		(118	)		—		—			3,182		(118	)
		495,804		(11,035	)		84,754		(5,925	)		580,558		(16,960	)
Equity securities		36,391		(3,223	)		386		(93	)		36,777		(3,316	)
Held-to-maturity Securities:
Japanese national government bonds		1,812,196		(48,149	)		—		—			1,812,196		(48,149	)
Japanese local government bonds		531		(2	)		—		—			531		(2	)
Japanese corporate bonds		20,788		(67	)		—		—			20,788		(67	)
Foreign corporate bonds		194		(3	)		—		—			194		(3	)
		1,833,709		(48,221	)		—		—			1,833,709		(48,221	)
Total		2,365,904		(62,479	)		85,140		(6,018	)		2,451,044		(68,497	)

	Yen in millions
	March 31, 2012
	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		55,450		(877	)		3,048		(2	)		58,498		(879	)
Japanese local government bonds		2,364		(1	)		—		—			2,364		(1	)
Japanese corporate bonds		1,034		(196	)		25,243		(28	)		26,277		(224	)
Foreign corporate bonds		68,277		(6,065	)		83,650		(998	)		151,927		(7,063	)
Other		335		(6	)		—		—			335		(6	)
		127,460		(7,145	)		111,941		(1,028	)		239,401		(8,173	)
Equity securities		4,337		(318	)		280		(1,195	)		4,617		(1,513	)
Held-to-maturity Securities:
Japanese national government bonds		—		—			333,702		(4,499	)		333,702		(4,499	)
Japanese local government bonds		70		(0	)		—		—			70		(0	)
Japanese corporate bonds		—		—			—		—			—		—
Foreign corporate bonds		—		—			—		—			—		—
		70		(0	)		333,702		(4,499	)		333,772		(4,499	)
Total		131,867		(7,463	)		445,923		(6,722	)		577,790		(14,185	)