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, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net Income (Loss)	$ (486)	$ 2,946	$ 1,216
Denominator:
Basic weighted-average common shares outstanding	158.8	161.0	161.2
Diluted weighted-average shares	158.8	162.7	162.4
Earnings (loss) per share:
Basic (in usd per share)	$ (3.06)	$ 18.29	$ 7.55
Diluted (in usd per share)	$ (3.06)	$ 18.10	$ 7.49
Number of anti-dilutive share-based awards	2.2	0.8	1.4
Stock Options
Denominator:
Effect of stock-based awards	0.0	1.1	0.7
Restricted Stock Units (RSUs)
Denominator:
Effect of stock-based awards	0.0	0.6	0.5