Note 3. Cash and Investments

Cash, cash equivalents, and marketable securities consisted of the following (in millions):


	As of December 31,
	2010		2011
Cash and cash equivalents:
Cash	$	4,652	$	4,712
Cash equivalents:
Time deposits		973		534
Money market and other funds⁽¹⁾		7,547		4,462
U.S. government agencies		0		275
U.S. government notes		300		0
Foreign government bonds		150		0
Corporate debt securities		8		0

Total cash and cash equivalents		13,630		9,983

Marketable securities:
Time deposits		307		495
U.S. government agencies		1,857		6,226
U.S. government notes		3,930		11,579
Foreign government bonds		1,172		1,629
Municipal securities		2,503		1,794
Corporate debt securities		5,742		6,112
Agency residential mortgage-backed securities		5,673		6,501
Marketable equity securities		161		307

Total marketable securities		21,345		34,643

Total cash, cash equivalents, and marketable securities	$	34,975	$	44,626

⁽¹⁾

The balances at December 31, 2010 and December 31, 2011 included $1.6 billion and $1.3 billion of cash collateral received in connection with our securities lending program, which was invested in reverse repurchase agreements maturing within three months. See below for further discussion on this program.

The following tables summarize unrealized gains and losses related to our investments in marketable securities designated as available-for-sale (in millions):


	As of December 31, 2010
	Adjusted Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Time deposits	$	307	$	0	$	0		$	307
U.S. government agencies		1,864		1		(8	)		1,857
U.S. government notes		3,950		30		(50	)		3,930
Foreign government bonds		1,154		23		(5	)		1,172
Municipal securities		2,492		16		(5	)		2,503
Corporate debt securities		5,600		167		(25	)		5,742
Agency residential mortgage-backed securities		5,649		56		(32	)		5,673
Marketable equity security		150		11		0			161

Total	$	21,166	$	304	$	(125	)	$	21,345


	As of December 31, 2011
	Adjusted Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Time deposits	$	495	$	0	$	0		$	495
U.S. government agencies		6,211		15		0			6,226
U.S. government notes		11,475		104		0			11,579
Foreign government bonds		1,608		32		(11	)		1,629
Municipal securities		1,775		19		0			1,794
Corporate debt securities		6,023		187		(98	)		6,112
Agency residential mortgage-backed securities		6,359		147		(5	)		6,501
Marketable equity securities		228		79		0			307

Total	$	34,174	$	583	$	(114	)	$	34,643

Gross unrealized gains and losses on cash equivalents were not material at December 31, 2010 and December 31, 2011.

We recognized gross realized gains of $212 million and $381 million for the years ended December 31, 2010 and 2011. We recognized gross realized losses of $27 million and $127 million for the years ended December 31, 2010 and 2011. We determine realized gains or losses on the sale of marketable securities on a specific identification method, and we reflect such gains and losses as a component of interest and other income, net, in our accompanying Consolidated Statements of Income.

The following table summarizes the estimated fair value of our investments in marketable securities, excluding the marketable equity securities, designated as available-for-sale and classified by the contractual maturity date of the securities (in millions):


	As of December 31, 2011
Due in 1 year	$	13,242
Due in 1 year through 5 years		7,482
Due in 5 years through 10 years		5,525
Due after 10 years		8,087

Total	$	34,336

The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of December 31, 2010 and 2011, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in millions):


	As of December 31, 2010
	Less than 12 Months
	Fair Value		Unrealized Loss
U.S. government agencies	$	831	$	(8	)
U.S. government notes		2,225		(50	)
Foreign government bonds		129		(5	)
Municipal securities		962		(5	)
Corporate debt securities		1,061		(25	)
Agency residential mortgage-backed securities		1,675		(32	)

Total	$	6,883	$	(125	)

As of December 31, 2010, we did not have any investments in marketable securities that were in an unrealized loss position for 12 months or greater.


	As of December 31, 2011
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Foreign government bonds	$	302	$	(11	)	$	6	$	0		$	308	$	(11	)
Corporate debt securities		2,160		(97	)		17		(1	)		2,177		(98	)
Agency residential mortgage-backed securities		716		(3	)		19		(2	)		735		(5	)

Total	$	3,178	$	(111	)	$	42	$	(3	)	$	3,220	$	(114	)

Investment in a Marketable Equity Security

During the fourth quarter of 2011, we recorded an other-than-temporary impairment charge of $88 million related to our investment in Clearwire Corporation. This amount was included in interest and other income, net in the accompanying Consolidated Statement of Income.

Securities Lending Program

From time to time, we enter into securities lending agreements with financial institutions to enhance investment income. We loan selected securities which are secured by collateral in the form of cash or securities. Cash collateral is invested in reverse repurchase agreements. We classify loaned securities as cash equivalents or marketable securities on the accompanying Consolidated Balance Sheets. We record the cash collateral as an asset with a corresponding liability. We classify reverse repurchase agreements maturing within three months as cash equivalents and those longer than three months as receivable under reverse repurchase agreements on the accompanying Consolidated Balance Sheets. For lending agreements collateralized by securities, we do not record an asset or liability as we are not permitted to sell or repledge the associated collateral.