Net Earnings Per Common Share (Basic And Diluted Net Earnings Per Common Share Based On The Weighted Average Outstanding Shares) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Basic:
Net income	$ 126	$ 175	$ 175	$ 204	$ 284	$ 217	$ 203	$ 203	$ 680	$ 907	$ 1,129
Less common and preferred dividends									277	269	261
Less impact from redemption of preferred stock									0	0	3
Undistributed earnings									403	638	865
Less undistributed earnings applicable to nonvested shares									4	5	7
Undistributed earnings applicable to common shares									399	633	858
Distributed earnings applicable to common shares									243	237	230
Total earnings applicable to common shares									$ 642	$ 870	$ 1,088
Weighted average common shares outstanding (in shares)									147,748	150,064	159,913
Net earnings per common share (in dollars per share)	$ 0.78	$ 1.13	$ 1.11	$ 1.33	$ 1.84	$ 1.40	$ 1.29	$ 1.27	$ 4.35	$ 5.80	$ 6.80
Diluted:
Dilutive effect of stock options (in shares)									8	207	321
Weighted average diluted common shares outstanding (in shares)									147,756	150,271	160,234
Net earnings per common share (in dollars per share)	$ 0.78	$ 1.13	$ 1.11	$ 1.33	$ 1.84	$ 1.40	$ 1.29	$ 1.27	$ 4.35	$ 5.79	$ 6.79