Selected Balance Sheet Data Accounts Receivable, Net (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Accounts receivable, net
Accounts receivable	$ 110	$ 102
Less allowance for bad debts	(9)	(8)
Accounts receivable, net	$ 101	$ 94

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant