Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Summary of Marketable Securities [Table Text Block]

	2016						2015
	Cost		Unrealized Gains (Losses)		Fair Value		Cost		Unrealized Gains (Losses)		Fair Value
U.S. government securities	$	2	$	—	$	2	$	38	$	—	$	38
Corporate securities	2				2		42				42
Certificates of deposit	22				22		18				18
Other	4				4		62		2		64
Total marketable securities	$	30	$	—	$	30	$	160	$	2	$	162