Net Income Per Common Share (Basic And Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 351	$ 262	$ 801	$ 940
Income allocated to participating securities	2	1	4	4
Preferred stock dividends	6	6	17	17
Net income attributable to common shares	$ 343	$ 255	$ 780	$ 919
Basic average common shares	131.0	133.0	131.0	136.0
Basic net income per common share	$ 2.63	$ 1.92	$ 5.96	$ 6.75
Basic average common shares	131.0	133.0	131.0	136.0
Net effect of the assumed exercise of stock awards	1.0	1.0	2.0	2.0
Diluted average common shares	132.0	134.0	133.0	138.0
Diluted net income per common share	$ 2.60	$ 1.90	$ 5.88	$ 6.67