Credit Losses (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Credit losses
Accounts receivable, net	$ 767	$ 621	$ 939
Allowance for doubtful accounts	$ 30	$ 32	$ 34

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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