CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock, Common [Member]
Beginning Balance at Dec. 31, 2020	$ 3,020.4	$ 292.8	$ 274.4	$ 4,786.0	$ (77.6)	$ (2,255.2)
Beginning Balance (in shares) at Dec. 31, 2020		292.8				(47.4)
Net Income (Loss)	827.5	$ 0.0	0.0	827.5	0.0	$ 0.0
Other comprehensive (loss) income	9.4	0.0	0.0	0.0	9.4	0.0
Cash dividends	(247.5)	0.0	0.0	(247.5)	0.0	0.0
Stock purchases	(500.0)	0.0	(10.0)	0.0	0.0	$ (510.0)
Stock purchases (in shares)						(5.7)
Stock based compensation expense and stock option plan transactions	123.4	$ 0.0	25.9	0.0	0.0	$ 97.5
Stock based compensation expense and stock option plan transactions (in shares)		0.0				2.8
Ending Balance at Dec. 31, 2021	3,233.2	$ 292.8	310.3	5,366.0	(68.2)	$ (2,667.7)
Ending Balance (in shares) at Dec. 31, 2021		292.8				(50.3)
Net Income (Loss)	413.9	$ 0.0	0.0	413.9	0.0	$ 0.0
Other comprehensive (loss) income	38.9	0.0	0.0	0.0	38.9	0.0
Cash dividends	(255.0)	0.0	0.0	(255.0)	0.0	0.0
Stock purchases	0.0	0.0	20.0	0.0	0.0	$ (20.0)
Stock purchases (in shares)						(0.2)
Stock based compensation expense and stock option plan transactions	58.9	$ 0.9	35.9	(0.3)	0.0	$ 22.4
Stock based compensation expense and stock option plan transactions (in shares)		0.9				0.7
Ending Balance at Dec. 31, 2022	3,489.9	$ 293.7	366.2	5,524.6	(29.3)	$ (2,665.3)
Ending Balance (in shares) at Dec. 31, 2022		293.7				(49.8)
Net Income (Loss)	755.6	$ 0.0	0.0	755.6	0.0	$ 0.0
Other comprehensive (loss) income	2.1	0.0	0.0	0.0	2.1	0.0
Cash dividends	(266.5)	0.0	0.0	(266.5)	0.0	0.0
Stock purchases	(300.1)	0.0	0.0	0.0	0.0	$ (300.1)
Stock purchases (in shares)						(3.3)
Stock based compensation expense and stock option plan transactions	174.4	$ 0.0	88.6	(1.4)	0.0	$ 87.2
Stock based compensation expense and stock option plan transactions (in shares)		0.0				2.5
Ending Balance at Dec. 31, 2023	$ 3,855.4	$ 293.7	$ 454.8	$ 6,012.3	$ (27.2)	$ (2,878.2)
Ending Balance (in shares) at Dec. 31, 2023		293.7				(50.6)