Available-for-sale investments (Tables)

9 Months Ended

Sep. 30, 2012

Investments, Debt and Equity Securities [Abstract]

Amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of available-for-sale investments by type of security

The amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of available-for-sale investments by type of security were as follows (in millions):

Type of security as of September 30, 2012	Amortized cost		Gross unrealized gains		Gross unrealized losses			Estimated fair value
U.S. Treasury securities	$	3,936	$	24	$	—		$	3,960
Other government-related debt securities:
Obligations of U.S. government agencies and FDIC-guaranteed bank debt	1,180		18		—			1,198
Foreign and other	1,656		56		—			1,712
Corporate debt securities:
Financial	3,158		99		(1		)	3,256
Industrial	4,208		114		(4		)	4,318
Other	420		12		—			432
Residential mortgage-backed securities	1,834		9		(7		)	1,836
Other mortgage- and asset-backed securities	2,062		10		(6		)	2,066
Money market mutual funds	4,000		—		—			4,000
Other short-term interest-bearing securities	2,105		—		—			2,105
Total debt security investments	24,559		342		(18		)	24,883
Equity securities	50		2		—			52
Total available-for-sale investments	$	24,609	$	344	$	(18	)	$	24,935

Type of security as of December 31, 2011	Amortized cost		Gross unrealized gains		Gross unrealized losses			Estimated fair value
U.S. Treasury securities	$	3,878	$	68	$	—		$	3,946
Other government-related debt securities:
Obligations of U.S. government agencies and FDIC-guaranteed bank debt	1,548		23		—			1,571
Foreign and other	441		9		—			450
Corporate debt securities:
Financial	2,493		30		(15		)	2,508
Industrial	3,077		79		(10		)	3,146
Other	280		9		—			289
Residential mortgage-backed securities	518		3		(3		)	518
Other mortgage- and asset-backed securities	1,271		3		(7		)	1,267
Money market mutual funds	6,266		—		—			6,266
Total debt security investments	19,772		224		(35		)	19,961
Equity securities	42		—		—			42
Total available-for-sale investments	$	19,814	$	224	$	(35	)	$	20,003

Fair values of available-for-sale investments by classification in the Consolidated Balance Sheets

The fair values of available-for-sale investments by classification in the Condensed Consolidated Balance Sheets were as follows (in millions):

Classification in the Condensed Consolidated Balance Sheets	September 30, 2012		December 31, 2011
Cash and cash equivalents	$	5,332	$	6,266
Marketable securities	19,551		13,695
Other assets — noncurrent	52		42
Total available-for-sale investments	$	24,935	$	20,003

Fair values of available-for-sale debt security investments by contractual maturity

The fair values of available-for-sale debt security investments by contractual maturity, except for mortgage- and asset- backed securities that do not have a single maturity date, were as follows (in millions):

Contractual maturity	September 30, 2012		December 31, 2011
Maturing in one year or less	$	8,501	$	6,791
Maturing after one year through three years	4,998		5,855
Maturing after three years through five years	5,861		5,379
Maturing after five years through ten years	1,621		151
Mortgage- and asset-backed securities	3,902		1,785
Total debt security investments	$	24,883	$	19,961