Segment Information and Concentrations - Revenue by Products and Services (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Revenue from External Customer [Line Items]
Total revenue	$ 1,503	$ 1,536
Product revenue
Revenue from External Customer [Line Items]
Total revenue	474	539
Professional services and installation services revenue
Revenue from External Customer [Line Items]
Total revenue	227	238
Recurring revenue, including maintenance, cloud revenue and payments
Revenue from External Customer [Line Items]
Total revenue	802	759
Software
Revenue from External Customer [Line Items]
Total revenue	474	467
Services
Revenue from External Customer [Line Items]
Total revenue	636	585
Hardware
Revenue from External Customer [Line Items]
Total revenue	$ 393	$ 484

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration