Segment, Other Supplemental Information and Concentrations - Schedule of Revenue by Geographical Area (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 494	$ 459	$ 478	$ 468	$ 588	$ 526	$ 544	$ 506	$ 1,899	$ 2,164	$ 2,156
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									953	1,018	1,089
Americas (excluding United States)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									104	108	106
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 492	$ 587	$ 567