Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130532-203044

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

Name:	us-gaap_ContractWithCustomerLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Revenue - Narrative (Details) $ in Millions	12 Months Ended
Revenue - Narrative (Details) $ in Millions	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) discontinuedOperation	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Number of operating segments		1	1
Number of reportable segments \| segment			1
Maximum
Disaggregation of Revenue [Line Items]
Duration of contract	1 year
Contract liability \| $	$ 1	$ 1	$ 1	$ 1