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Stock-based Compensation (Schedule of Stock Option Exercises) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock Option Aggregate Disclosures [Abstract]
Intrinsic value of stock options exercised	$ 23	$ 48
Cash received from option exercises	30	33
Treasury shares repurchased for employee payroll taxes	(6)	(8)
Tax benefit realized from option exercises	4	11
Aggregate grant-date fair value of stock options vested	$ 14	$ 14

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Value of treasury shares repurchased during period for employee payroll taxes related to share-based compensation awards.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2A
-Subparagraph (a)
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Amount of cash inflow from exercise of option under share-based payment arrangement.

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