Stock-Based Compensation (Schedule of Stock-Based Compensation Activity) (Details) - Stock Option $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Outstanding at January 1, 2019 \| shares	5,892
Granted \| shares	1,568
Exercised \| shares	(1,909)
Forfeited or expired \| shares	(160)
Outstanding at December 31, 2019 \| shares	5,391
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Outstanding at January 1, Weighted-Average Exercise Price \| $ / shares	$ 115.26
Granted, Weighted-Average Exercise Price \| $ / shares	139.18
Exercised, Weighted-Average Exercise Price \| $ / shares	113.58
Forfeited or expired, Weighted-Average Exercise Price \| $ / shares	124.97
Outstanding at December 31, Weighted-Average Exercise Price \| $ / shares	$ 123.14
Exercisable at December 31, 2019 \| shares	2,813
Exercisable at December 31, Weighted-Average Exercise Price \| $ / shares	$ 116.94
Outstanding at December 31, Weighted-Average Remaining Contractual Term	7 years 9 months
Exercisable at December 31, Weighted-Average Remaining Contractual Term	5 years 4 months 2 days
Outstanding at December 31, Aggregate Intrinsic Value \| $	$ 70
Exercisable at December 31, Aggregate Intrinsic Value \| $	$ 50

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.