Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Summary of Marketable Securities

	2014						2013
	Cost		Unrealized Gains (Losses)		Fair Value		Cost		Unrealized Gains (Losses)			Fair Value
U.S. government securities	$	38	$	—	$	38	$	27	$	—		$	27
Corporate securities	36				36		30		(1		)	29
Certificates of deposit	23				23		21					21
Other	67		5		72		31		2			33
Total marketable securities	$	164	$	5	$	169	$	109	$	1		$	110