Supplemental Cash Flow Information (Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions		Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents		$ 1,091	$ 1,527
Restricted cash	[1]	2	2
Cash, cash equivalents and restricted cash		$ 1,093	$ 1,529	$ 1,249	$ 1,725

[1] The restricted cash balance is included within other current assets on the consolidated balance sheets