Valuation of Debt and Equity Investments and Certain Liabilities (Tables)

12 Months Ended

Dec. 31, 2015

Details of our investments are as follows:

	December 31, 2015						December 31, 2014
	Cash and Cash		Short-Term		Long-Term		Cash and Cash		Short-Term		Long-Term
	Equivalents		Investments		Investments		Equivalents		Investments		Investments
Measured at fair value:
Available-for-sale securities:
Money market funds	$	395	$	—	$	—	$	522	$	—	$	—
Corporate obligations		132		285		—		97		390		—
U.S. Government agency and Treasury securities		245		1,933		—		365		1,952		—
Trading securities:
Mutual funds		—		—		187		—		—		185
Total		772		2,218		187		984		2,342		185

Other measurement basis:
Equity-method investments		—		—		25		—		—		27
Cost-method investments		—		—		9		—		—		12
Cash on hand		228		—		—		215		—		—
Total	$	1,000	$	2,218	$	221	$	1,199	$	2,342	$	224

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 December 31, 2015:

Due	Fair Value
One year or less	$	2,970
One to two years		20

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 December 31, 2015 and 2014. 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
	December 31, 2015		Level 1		Level 2
Assets:
Money market funds	$	395	$	395	$	—
Corporate obligations		417		—		417
U.S. Government agency and Treasury securities		2,178		1,828		350
Mutual funds		187		187		—
Total assets	$	3,177	$	2,410	$	767

Liabilities:
Deferred compensation	$	198	$	198	$	—
Total liabilities	$	198	$	198	$	—

	Fair Value
	December 31, 2014		Level 1			Level 2
Assets:
Money market funds	$	522	$	522	$	—
Corporate obligations		487		—		487
U.S. Government agency and Treasury securities		2,317		1,762		555
Mutual funds		185		185		—
Total assets	$	3,511	$	2,469	$	1,042

Liabilities:
Deferred compensation	$	202	$	202	$	—
Total liabilities	$	202	$	202	$	—