Credit Losses (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Credit Losses
Accounts receivable, net	$ 714	$ 623	$ 767
Allowance for doubtful accounts	$ 32	$ 33	$ 30

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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