Investments (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Debt Securities, Trading, and Equity Securities, FV-NI [Table Text Block]

The following table summarizes the fair value of investments held as of December 31, 2018 and December 31, 2017 (in millions):

	December 31, 2018		December 31, 2017
Debt securities	$	36	$	43
Equity securities	37		54
Total	$	73	$	97