Credit Losses (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Credit Losses
Accounts receivable, net	$ 623	$ 621
Allowance for doubtful accounts	$ 33	$ 32

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.

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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