Fair Value Measurements (Tables)

12 Months Ended

Mar. 31, 2011

Fair Value Measurements (Tables) [Abstract]

Fair value of assets and liabilities at fair value on recurring basis

The fair value of Sony’s assets and liabilities that are measured at fair value on a recurring basis at March 31, 2010 and 2011 are as follows:

	Yen in millions
	March 31, 2010
	Level 1		Level 2		Level 3		Total
Assets:
Trading securities		180,414		172,939		—		353,353
Available-for-sale securities
Debt securities
Japanese national government bonds		—		1,290,824		—		1,290,824
Japanese local government bonds		—		28,842		—		28,842
Japanese corporate bonds		4,937		358,187		1,097		364,221
Foreign corporate bonds		—		261,896		17,433		279,329
Other		365		10,736		—		11,101
Equity securities		160,128		6,682		3,936		170,746
Other investments*1		5,377		38		69,672		75,087
Derivative assets*2		—		23,796		—		23,796
Total assets		351,221		2,153,940		92,138		2,597,299
Liabilities:
Derivative liabilities*2		—		48,599		—		48,599
Total liabilities		—		48,599		—		48,599

	Yen in millions
	March 31, 2011
	Level 1		Level 2		Level 3		Total
Assets:
Trading securities		189,320		186,482		—		375,802
Available-for-sale securities
Debt securities
Japanese national government bonds		—		1,143,765		—		1,143,765
Japanese local government bonds		—		22,965		—		22,965
Japanese corporate bonds		—		329,057		4,581		333,638
Foreign corporate bonds		—		306,070		20,050		326,120
Other		—		7,933		—		7,933
Equity securities		141,408		4,667		3,968		150,043
Other investments*1		5,459		51		70,058		75,568
Derivative assets*2		—		15,110		—		15,110
Total assets		336,187		2,016,100		98,657		2,450,944
Liabilities:
Derivative liabilities*2		—		33,759		—		33,759
Total liabilities		—		33,759		—		33,759

*1	Other investments include certain private equity investments and certain hybrid financial instruments.
*2	Derivative assets and liabilities are recognized and disclosed on a gross basis.

Changes in fair value of level 3 assets and liabilities

The changes in fair value of level 3 assets and liabilities for the fiscal years ended March 31, 2010 and 2011 are as follows:

	Yen in millions
	Fiscal year ended March 31, 2010
	Assets
				Available-for-sale securities
				Debt securities
				Japanese			Foreign
	Trading			corporate			corporate			Equity			Other		Derivative
	securities			bonds			bonds			securities			investments		assets
Beginning balance		3,003			7,630			51,798			3,562			59,781		—
Total realized and unrealized gains (losses):
Included in earnings*1		181			(260	)		(404	)		(2	)		6,288		(69	)
Included in other comprehensive income (loss)		—			—			1,818			374			2,781		—
Purchases, issuances, sales and settlements		(562	)		(5,660	)		(4,247	)		2			822		(186	)
Transfers in and/or out of level 3*2*3		(2,622	)		(613	)		(31,532	)		—			—		255
Ending balance		—			1,097			17,433			3,936			69,672		—
Changes in unrealized gains (losses) relating to instruments still held at reporting date:
Included in earnings*1		—			—			(40	)		—			6,726		—

	Yen in millions
	Fiscal year ended March 31, 2011
	Assets
	Available-for-sale securities
	Debt securities
	Japanese			Foreign
	corporate			corporate			Equity		Other
	bonds			bonds			securities		investments
Beginning balance		1,097			17,433			3,936		69,672
Total realized and unrealized gains (losses):
Included in earnings*1		(13	)		(224	)		—		(3,332	)
Included in other comprehensive income (loss)		(18	)		(842	)		32		2,606
Purchases, issuances, sales and settlements		3,515			8,251			—		1,112
Transfers in and/or out of level 3*2		—			(4,568	)		—		—
Ending balance		4,581			20,050			3,968		70,058
Changes in unrealized gains (losses) relating to instruments still held at reporting date:
Included in earnings*1		(2	)		10			—		(3,779	)

*1	Earning effects are included in financial services revenue in the consolidated statements of income.
*2	Transfers into or out of level 3 are reported as the value as of the beginning of the period in which the transfer occurs.
*3	Certain corporate bonds were transferred into level 2 because the ability to corroborate significant inputs with market observable data became possible due to a significant recovery in credit markets.

Estimated fair value of Sony's financial instruments

The estimated fair values of Sony’s financial instruments are summarized as follows. The following summary excludes cash and cash equivalents, call loans, time deposits, notes and accounts receivable, trade, call money, short-term borrowings, notes and accounts payable, trade and deposits from customers in the banking business because the carrying values of these financial instruments approximated their fair values due to their short-term nature. The summary also excludes debt and equity securities which are disclosed in Note 7.

	Yen in millions
	March 31, 2010				March 31, 2011
	Carrying		Estimated		Carrying		Estimated
	amount		fair value		amount		fair value
Long-term debt including the current portion		1,160,029		1,168,354		921,849		928,820
Investment contracts included in policyholders’ account in the life insurance business		306,625		307,656		322,649		320,036
Housing loans in the banking business		555,105		612,830		656,047		714,985