3. Available-for-Sale Investments

The following is a summary of the fair value of available-for-sale securities (in millions):


	Amortized cost December 31,				Fair value December 31,
	2011		2010		2011		2010
Bonds, notes and other securities:
U.S. government and agencies	$	1,150	$	1,734	$	1,155	$	1,737
Other debt securities		6		11		9		15
Total short-term investments	$	1,156	$	1,745	$	1,164	$	1,752
Asset-backed securities	$	57	$	64	$	35	$	45
Total long-term investments	$	57	$	64	$	35	$	45

We do not intend to sell, nor do we believe it is more likely than not that we would be required to sell, the long-term investment asset-backed securities (which are collateralized by mortgages) before recovery of their amortized cost basis. It is possible that a significant degradation in the delinquency or foreclosure rates in the underlying assets could cause further temporary or other-than-temporary impairments in the future.

The following table summarizes the contractual maturities of available-for-sale securities at December 31, 2011 (in millions):

Less than one year	$ 835
Due in 1-5 years	320
Due in 5-10 years	0
Due after 10 years (1)	44
Total	$1,199

(1)	Included in the maturity table is $35 million of asset-based securities that mature over time and are being reported at their final maturity dates.

The following table provides the fair value and gross unrealized losses of the Company's investments and unrealized losses that are not deemed to be other-than-temporarily impaired, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2011 and 2010 (in millions):


	Number of securities in a loss position	December 31, 2011
		12 months or greater				Total
		Fair value		Unrealized losses (1)		Fair value		Unrealized losses
Asset-backed securities	22	$	35	$	(23)	$	35	$	(23)
Total long-term investments	22	$	35	$	(23)	$	35	$	(23)

(1)	Unrealized losses in securities less than 12 months were not significant.


	Number of securities in a loss position	December 31, 2010
		12 months or greater				Total
		Fair value		Unrealized losses (1)		Fair value		Unrealized losses
Asset-backed securities	22	$	45	$	(20)	$	45	$	(20)
Total long-term investments	22	$	45	$	(20)	$	45	$	(20)

(1) Unrealized losses in securities less than 12 months were not significant.

The following table provides the gross realized gains and losses for the twelve months ended December 31, 2011, 2010 and 2009 (in millions):


	December 31,
	2011		2010		2009
Gross realized gains	$	0	$	0	$	2
Gross realized losses	$	0	$	1	$	(6)

A roll forward of the changes in credit losses recognized in earnings for the twelve months ended December 31, 2011 and 2010 and nine months ended December 31, 2009 (in millions):


	2011		2010			2009*
Beginning balance of credit losses, January 1	$	4	$		2	$	0
Additions for credit losses not previously recognized in earnings		1			2		2
Balance of credit losses, December 31	$	5	$	4		$	2

* The standard was implemented April 1, 2009. Therefore, there are no credit losses recognized in the first quarter of 2009.

The $1 million loss in 2011 and $2 million loss in 2010 and 2009 represents management's estimate of credit losses inherent in the securities considering projected cash flows using assumptions of delinquency rates, loss severities, and other estimates of future collateral performance. These credit losses are limited to asset-backed securities in our investment portfolio.

As of December 31, 2011 and 2010, for securities that have credit losses, an other than temporary impairment loss of $18 million and $16 million, respectively, is recognized in accumulated other comprehensive income.

Proceeds from sales and maturities of short-term investments totaled $3.2 billion, $2.1 billion, and $1.3 billion in 2011, 2010, and 2009, respectively.