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Share-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	$ 20			$ 20
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options	195			$ 195
Treasury Stock, Shares, Acquired				14,800
Treasury stock purchases				$ 1,120
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 3,550			$ 3,550
Dividends Payable, Date Declared	Sep. 09, 2021	May 19, 2021	Mar. 25, 2021
Dividends Payable, Amount Per Share	$ 0.22	$ 0.22	$ 0.22	$ 0.22
Dividends Payable, Date to be Paid	Oct. 12, 2021	Jul. 13, 2021	Apr. 20, 2021
Dividends Payable, Date of Record	Sep. 27, 2021	Jun. 28, 2021	Apr. 06, 2021
Dividends Payable	$ 67			$ 67	$ 69
2021 Share Repurchase Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount	3,750			$ 3,750
Stock Repurchase Program Expiration Date				Dec. 31, 2023
2017 Share Repurchase Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount	$ 3,700			$ 3,700
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of recognition for remaining share-based compensation expense				1 year 4 months 20 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of recognition for remaining share-based compensation expense				2 years 1 month 17 days