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Share-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 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, Share-based Awards Other than Options	$ 249		$ 249
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	28		$ 28
Treasury Stock, Shares, Acquired			10,100
Treasury stock purchases			$ 750
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 3,930		$ 3,930
Dividends Payable, Date Declared	May 19, 2021	Mar. 25, 2021
Dividends Payable, Amount Per Share	$ 0.22	$ 0.22	$ 0.22
Dividends Payable, Date to be Paid	Jul. 13, 2021	Apr. 20, 2021
Dividends Payable, Date of Record	Jun. 28, 2021	Apr. 06, 2021
Dividends Payable	$ 68		$ 68	$ 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 7 months 2 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 2 months 23 days