Segment Information and Concentrations - Revenue by Geography (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,589	$ 1,783	$ 4,576	$ 5,029
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	962	1,104	2,740	3,053
Europe, Middle East and Africa (EMEA)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	424	458	1,234	1,329
Asia Pacific (APJ)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 203	$ 221	$ 602	$ 647