Cash and Cash Equivalents (Tables)

12 Months Ended

Dec. 31, 2018

Cash and Cash Equivalents [Abstract]

Components of cash and cash equivalents

The following table summarizes the components of our cash and cash equivalents (amounts in millions):

	At December 31,
	2018		2017
Cash	$	268	$	269
Foreign government treasury bills	32		39
Money market funds	3,925		4,405
Cash and cash equivalents	$	4,225	$	4,713