Net Income Per Common Share (Calculations For Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net Income	$ 2,946	$ 1,216	$ 1,997
Denominator:
Basic weighted-average common shares outstanding	161.0	161.2	163.2
Diluted weighted-average shares	162.7	162.4	165.1
Earnings per share:
Basic (in usd per share)	$ 18.29	$ 7.55	$ 12.24
Diluted (in usd per share)	$ 18.10	$ 7.49	$ 12.10
Number of anti-dilutive share-based awards	0.8	1.4	0.0
Stock Options
Denominator:
Effect of stock-based awards	1.1	0.7	1.2
Restricted Stock Units (RSUs)
Denominator:
Effect of stock-based awards	0.6	0.5	0.7