CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	AOCI Attributable to Parent	Retained Earnings	Noncontrolling Interest
Dividends paid:
Noncontrolling interests						$ 0.0
Balance at Dec. 31, 2020		$ 158.0	$ 2,137.8	$ (689.9)	$ (155.1)
Common stock repurchased and retired		(4.7)	(247.2)
Common stock issued for:
Stock options exercised	$ 72.4	3.4	69.0
Other transactions		0.1	3.3
Stock-based compensation			6.7
Total other comprehensive (loss) income	201.9			201.9
Net income (loss)	1,296.7				1,296.7
Dividends paid:
Common stock ($0.80 per share)					(127.8)
Balance at Dec. 31, 2021	2,652.2	$ 156.8	1,969.6	(488.0)	1,013.8
Dividends paid:
Net loss attributable to noncontrolling interests	0.0					0.0
Proceeds from (Payments to) Noncontrolling Interests						0.0
Common dividends per share (in dollars per share)		$ 0.80
Noncontrolling interests						0.0
Total equity	2,652.2
Common stock repurchased and retired		$ (25.7)	(1,325.0)
Stock options exercised	25.7	1.1	24.6
Other transactions		0.1	3.0
Stock-based compensation			10.5
Total other comprehensive (loss) income	(7.9)			(7.9)
Net income (loss)	1,326.9				1,326.9
Common stock ($0.80 per share)					(116.2)
Balance at Dec. 31, 2022	2,543.6	$ 132.3	682.7	(495.9)	2,224.5
Dividends paid:
Net loss attributable to noncontrolling interests	0.0					0.0
Proceeds from (Payments to) Noncontrolling Interests						0.0
Common dividends per share (in dollars per share)		$ 0.80
Noncontrolling interests	0.0					0.0
Total equity	2,543.6
Common stock repurchased and retired		$ (13.3)	(698.0)
Stock options exercised	25.4	1.0	24.4
Other transactions		0.2	1.6
Stock-based compensation			14.1
Total other comprehensive (loss) income	(0.4)			(0.4)
Net income (loss)	452.0				460.2
Common stock ($0.80 per share)					(101.0)
Balance at Dec. 31, 2023	2,232.4	$ 120.2	$ 24.8	$ (496.3)	$ 2,583.7
Dividends paid:
Net loss attributable to noncontrolling interests	(8.2)					(8.2)
Proceeds from (Payments to) Noncontrolling Interests						44.1
Common dividends per share (in dollars per share)		$ 0.80
Noncontrolling interests	35.9					$ 35.9
Total equity	$ 2,268.3