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

3 Months Ended

Mar. 31, 2018

Details of our investments are as follows:

	March 31, 2018						December 31, 2017
	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 debt securities:
Money market funds	$	369	$	—	$	—	$	525	$	—	$	—
Corporate obligations		413		764		—		172		698		—
U.S. government agency and Treasury securities		699		1,598		—		700		2,115		—
Trading securities:
Mutual funds		—		—		243		—		—		236
Total		1,481		2,362		243		1,397		2,813		236

Other measurement basis:
Equity-method investments		—		—		24		—		—		26
Non-marketable equity investments		—		—		4		—		—		6
Cash on hand		236		—		—		259		—		—
Total	$	1,717	$	2,362	$	271	$	1,656	$	2,813	$	268

Aggregate Maturities of Available-for-sale Investments

The following table presents the aggregate maturities of our available-for-sale investments as of March 31, 2018:

Due	Fair Value
One year or less	$	3,833
One to two years		10

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. 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.

	March 31, 2018						December 31, 2017
	Level 1		Level 2		Total		Level 1		Level 2		Total
Assets:
Money market funds	$	369	$	—	$	369	$	525	$	—	$	525
Corporate obligations		—		1,177		1,177		—		870		870
U.S. government agency and Treasury securities		2,247		50		2,297		2,765		50		2,815
Mutual funds		243		—		243		236		—		236
Total assets	$	2,859	$	1,227	$	4,086	$	3,526	$	920	$	4,446

Liabilities:
Deferred compensation	$	256	$	—	$	256	$	255	$	—	$	255
Total liabilities	$	256	$	—	$	256	$	255	$	—	$	255