Cash, Cash Equivalents, and Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value by Balance Sheet Grouping

The following table summarizes, by major security type, our cash, cash equivalents, and marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in millions):

											December 31,
	March 31, 2013										2012
	Cost or		Gross		Gross			Total			Total
	Amortized		Unrealized		Unrealized			Estimated			Estimated
	Cost		Gains		Losses			Fair Value			Fair Value
Cash	$	2,228	$	—	$	—		$	2,228		$	2,595
Level 1 securities:
Money market funds		2,424		—		—			2,424			5,561
Equity securities		3		—		—			3			2
Level 2 securities:
Foreign government and agency securities		679		6		—			685			772
U.S. government and agency securities		1,983		3		(2	)		1,984			1,810
Corporate debt securities		654		5		—			659			725
Asset-backed securities		55		—		—			55			49
Other fixed income securities		33		—		—			33			33
	$	8,059	$	14	$	(2	)		8,071			11,547
Less: Restricted cash, cash equivalents, and marketable securities (1)									(176	)		(99	)
Total cash, cash equivalents, and marketable securities								$	7,895		$	11,448

(1) We are required to pledge or otherwise restrict a portion of our cash, cash equivalents, and marketable securities as collateral for standby and trade letters of credit, guarantees, debt and real estate lease agreements. We classify cash and marketable securities with use restrictions of less than twelve months as “Accounts receivable, net and other” and of twelve months or longer as non-current “Other assets” on our consolidated balance sheets. See “Note 3 — Commitments and Contingencies.”

Investments Classified by Contractual Maturity Date

The following table summarizes the contractual maturities of our cash equivalent and marketable fixed-income securities as of March 31, 2013 (in millions):

	Amortized		Estimated
	Cost		Fair Value
Due within one year	$	3,565	$	3,568
Due after one year through five years		1,986		1,994
Due after five years		277		278
	$	5,828	$	5,840