Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 41	$ 41
Common stock authorized (in shares)	2,500,000,000	2,500,000,000
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock issued (in shares)	648,446,534	647,416,633
Treasury stock (in shares)	211,771,827	206,390,806

Amount of allowance for credit loss on accounts receivable, classified as current.

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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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