Marketable Securities

3 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Marketable Securities [Text Block]

Marketable Securities

	March 31, 2019						December 31, 2018
	Cost		Unrealized Gain (Loss)		Fair Value		Cost		Unrealized Gain (Loss)		Fair Value
U.S. government securities	$	2	$	—	$	2	$	2	$	—	$	2
Corporate securities	4				4		4				4
Certificates of deposit	14				14		15				15
Total marketable securities	$	20	$	—	$	20	$	21	$	—	$	21

U.S. government securities include bonds issued by government-sponsored agencies and Treasury notes. Corporate securities are primarily debt securities. U.S. government securities, corporate debt and certificates of deposit maturing in one year or less, after one year through five years and after five years through ten years total $15, $2 and $3 at March 31, 2019.