Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Summary of Marketable Securities

	March 31, 2014						December 31, 2013
	Cost		Unrealized Gain (Loss)		Fair Value		Cost		Unrealized Gain (Loss)			Fair Value
U.S. government securities	$	38	$	—	$	38	$	27	$	—		$	27
Corporate securities	33				33		30		(1		)	29
Certificates of deposit	22				22		21					21
Other	48		3		51		31		2			33
Total marketable securities	$	141	$	3	$	144	$	109	$	1		$	110