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Stock-based Compensation (Schedule Of Stock Option Exercises) (Details) - Stock Options [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Option Aggregate Disclosures [Abstract]
Intrinsic value of stock options exercised	$ 120	$ 193	$ 83
Cash received from option exercises	95	130	76
Treasury shares repurchased for employee payroll taxes	(24)	(37)	(20)
Tax benefit realized from option exercises	28	48	21
Aggregate grant-date fair value of stock options vested	$ 15	$ 15	$ 19

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

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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