Segment Information and Concentrations - Revenue by Geography (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,484	$ 1,710	$ 2,987	$ 3,246
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	886	1,029	1,778	1,949
Europe, Middle East and Africa (EMEA)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	407	452	810	871
Asia Pacific (APJ)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 191	$ 229	$ 399	$ 426