Earnings Per Share (Reconciliation of the Numerators and Denominators of the Basic and Diluted Per Shares) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Net income	$ 205.0	$ 105.0	$ 457.0	$ 302.0	$ 517.0	$ 1,170.0
Shares:
Weighted average outstanding shares	67	67	67	67
Equivalent shares from outstanding stock awards	1	1	1	1
Denominator for diluted calculation	68	68	68	68
Diluted earnings per share	$ 3.05	$ 1.55	$ 6.77	$ 4.46
Basic earnings per share	$ 3.09	$ 1.57	$ 6.86	$ 4.50
Net Income (Loss) Attributable to Noncontrolling Interest	$ 2.0	$ 1.0	$ 3.0	$ 1.0	4.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 207.0	$ 106.0	$ 460.0	$ 303.0	$ 521.0