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
	Mar. 31, 2024	Mar. 31, 2023
Basic:
Net income	$ 153	$ 204
Less common and preferred dividends	71	67
Undistributed earnings	82	137
Less undistributed earnings applicable to nonvested shares	1	1
Undistributed earnings applicable to common shares	81	136
Distributed earnings applicable to common shares	60	61
Total earnings applicable to common shares	$ 141	$ 197
Weighted average common shares outstanding (in shares)	147,338	148,015
Net earnings per common share (in dollars per share)	$ 0.96	$ 1.33
Diluted:
Dilutive effect of stock options (in shares)	5	23
Weighted average diluted common shares outstanding (in shares)	147,343	148,038
Net earnings per common share (in dollars per share)	$ 0.96	$ 1.33