Valuation of debt and equity investments and certain liabilities (Tables)

3 Months Ended

Mar. 31, 2012

Valuation of debt and equity investments and certain liabilities [Abstract]

Investments and Unrealized Gains and Losses

Details of our investments and related unrealized gains and losses included in AOCI are as follows:

	March 31, 2012						December 31, 2011
	Cash and Cash Equivalents		Short-term Investments		Long-term Investments		Cash and Cash Equivalents		Short-term Investments		Long-term Investments
Measured at fair value:
Available-for-sale securities
Money market funds	$	69	$	—	$	—	$	55	$	—	$	—
Corporate obligations	168		152		—		135		159		—
U.S. Government agency and Treasury securities	625		1,326		—		430		1,691		—
Auction-rate securities	—		—		24		—		—		41
Trading securities
Auction-rate securities	—		94		—		—		93		—
Mutual funds	—		—		159		—		—		169
Total	$	862	$	1,572	$	183	$	620	$	1,943	$	210
Other measurement basis:
Equity-method investments	$	—	$	—	$	33	$	—	$	—	$	32
Cost-method investments	—		—		23		—		—		23
Cash on hand	331		—		—		372		—		—
Total	$	1,193	$	1,572	$	239	$	992	$	1,943	$	265
Amounts included in AOCI from available-for-sale securities:
Unrealized gains (pre-tax)	$	—	$	1	$	—	$	—	$	—	$	—
Unrealized losses (pre-tax)	$	—	$	—	$	2	$	—	$	—	$	5

Aggregate Maturities of Investments in Debt Securities Classified as Available-for-sale

The following table presents the aggregate maturities of investments in debt securities classified as available for sale at March 31, 2012:

Due	Fair Value
One year or less	$	1,849
One to three years	491
Greater than three years (auction-rate securities)	24

Assets and Liabilities Accounted for at Fair Value

The following are our assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2012, and December 31, 2011.  These tables do not include cash on hand, assets held by our postretirement plans, or assets and liabilities that are measured at historical cost or any basis other than fair value.

	Fair Value
	March 31, 2012		Level 1		Level 2		Level 3
Assets:
Money market funds	$	69	$	69	$	—	$	—
Corporate obligations	320		—		320		—
U.S. Government agency and Treasury securities	1,951		730		1,221		—
Auction-rate securities	118		—		—		118
Mutual funds	159		159		—		—
Total assets	$	2,617	$	958	$	1,541	$	118
Liabilities:
Deferred compensation	173		173		—		—
Total liabilities	$	173	$	173	$	—	$	—

	Fair Value
	December 31, 2011		Level 1		Level 2		Level 3
Assets:
Money market funds	$	55	$	55	$	—	$	—
Corporate obligations	294		—		294		—
U.S. Government agency and Treasury securities	2,121		606		1,515		—
Auction-rate securities	134		—		—		134
Mutual funds	169		169		—		—
Total assets	$	2,773	$	830	$	1,809	$	134
Liabilities:
Deferred compensation	191		191		—		—
Total liabilities	$	191	$	191	$	—	$	—

Reconciliation of Change in Fair Value for Level 3 Assets

The following table summarizes the changes in fair values for Level 3 assets and liabilities for the periods ended March 31, 2012 and 2011:  

	Level 3
Changes in fair value during the period (pre-tax):	Auction-rate Securities			Contingent Consideration
Balance, December 31, 2010	$	257		$	8
Change in fair value of contingent consideration - included in operating profit	—			(8		)
Change in unrealized loss - included in AOCI	1			—
Redemptions and sales	(1		)	—
Balance, March 31, 2011	257			—
Change in unrealized loss - included in AOCI	(2		)	—
Redemptions and sales	(121		)	—
Balance, December 31, 2011	134			—
Change in unrealized loss - included in AOCI	5			—
Redemptions	(1		)	—
Sales	(20		)	—
Balance, March 31, 2012	$	118		$	—