Net Earnings Per Common Share - Basic and Diluted Net Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Basic:
Net income	$ 201	$ 175	$ 354	$ 379
Less common and preferred dividends	72	70	143	138
Undistributed earnings	129	105	211	241
Less undistributed earnings applicable to nonvested shares	1	1	2	2
Undistributed earnings applicable to common shares	128	104	209	239
Distributed earnings applicable to common shares	61	61	121	121
Total earnings applicable to common shares	$ 189	$ 165	$ 330	$ 360
Weighted average common shares outstanding (in shares)	147,115	147,692	147,227	147,852
Net earnings per common share (in dollars per share)	$ 1.28	$ 1.11	$ 2.24	$ 2.44
Diluted:
Total earnings applicable to common shares	$ 189	$ 165	$ 330	$ 360
Dilutive effect of stock options (in shares)	5	4	4	13
Weighted average common shares outstanding (in shares)	147,115	147,692	147,227	147,852
Weighted average diluted common shares outstanding (in shares)	147,120	147,696	147,231	147,865
Net earnings per common share (in dollars per share)	$ 1.28	$ 1.11	$ 2.24	$ 2.44