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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Net income	$ 206	$ 273	$ 344	$ 597
Income allocated to participating securities	1	2	2	3
Preferred stock dividends	5	5	11	11
Net income attributable to common shares	$ 200	$ 266	$ 331	$ 583
Basic average common shares (in shares)	133.0	132.0	133.0	132.0
Basic net income per common share (in dollars per share)	$ 1.50	$ 2.02	$ 2.49	$ 4.43
Basic average common shares (in shares)	133.0	132.0	133.0	132.0
Net effect of the assumed exercise of stock awards (in shares)	1.0	0.0	1.0	0.0
Diluted average common shares (in shares)	134.0	132.0	134.0	132.0
Diluted net income per common share (in dollars per share)	$ 1.49	$ 2.01	$ 2.47	$ 4.40