Short-Term and Long-Term Investments (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities [Table Text Block]

As of December 31, 2016, our short-term and long-term investments primarily consist of available-for-sale securities as follows (in millions):

	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Cetip equity securities	$	324	$	108	$	—	$	432
Mutual funds	23		—		—		23
Total available-for-sale securities	$	347	$	108	$	—	$	455

As of December 31, 2015, our short-term and long-term investments primarily consist of available-for-sale securities as follows (in millions):

	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Cetip equity securities	$	324	$	—	$	(25	)	$	299
Mutual funds	29		—		—			29
Total available-for-sale securities	$	353	$	—	$	(25	)	$	328