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

6 Months Ended

Jun. 30, 2013

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

Investments

Details of our investments are as follows:

	June 30, 2013						December 31, 2012
	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	$	277	$	—	$	—	$	211	$	—	$	—
Corporate obligations	73		271		—		188		325		—
U.S. Government agency and Treasury securities	675		1,793		—		795		2,224		—
Trading securities
Mutual funds	—		—		159		—		—		159
Total	$	1,025	$	2,064	$	159	$	1,194	$	2,549	$	159
Other measurement basis:
Equity-method investments	$	—	$	—	$	25	$	—	$	—	$	34
Cost-method investments	—		—		19		—		—		22
Cash on hand	155		—		—		222		—		—
Total	$	1,180	$	2,064	$	203	$	1,416	$	2,549	$	215

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 June 30, 2013:

Due	Fair Value
One year or less	$	2,799
One to three years	290

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 June 30, 2013, and December 31, 2012. For these periods, we had no Level 3 assets or liabilities. 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
	June 30, 2013		Level 1		Level 2
Assets:
Money market funds	$	277	$	277	$	—
Corporate obligations	344		—		344
U.S. Government agency and Treasury securities	2,468		1,517		951
Mutual funds	159		159		—
Total assets	$	3,248	$	1,953	$	1,295
Liabilities:
Deferred compensation	$	178	$	178	$	—
Total liabilities	$	178	$	178	$	—

	Fair Value
	December 31, 2012		Level 1		Level 2
Assets:
Money market funds	$	211	$	211	$	—
Corporate obligations	513		—		513
U.S. Government agency and Treasury securities	3,019		1,145		1,874
Mutual funds	159		159		—
Total assets	$	3,902	$	1,515	$	2,387
Liabilities:
Deferred compensation	$	174	$	174	$	—
Total liabilities	$	174	$	174	$	—

Reconciliation of Change in Fair Value for Level 3 Assets

The following table summarizes the change in the fair values for Level 3 assets:

	Level 3
Changes in fair value during the period (pre-tax):	Auction-rate Securities
Balance, December 31, 2011	$	134
Change in unrealized loss – included in AOCI	10
Redemptions	(84		)
Sales	(20		)
Balance, June 30, 2012	$	40