CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2022	$ 3,489.9	$ 293.7	$ (2,665.3)	$ 366.2	$ 5,524.6	$ (29.3)
Beginning Balance (in shares) at Dec. 31, 2022		293.7	(49.8)
Net income	203.2	$ 0.0	$ 0.0	0.0	203.2	0.0
Other comprehensive income (loss)	3.1	0.0	0.0	0.0	0.0	3.1
Cash dividends	(66.3)	0.0	0.0	0.0	(66.3)	0.0
Stock based compensation expense and stock option plan transactions	37.8	$ 0.0	$ 10.3	27.8	(0.3)	0.0
Stock based compensation expense and stock option plan transactions (in shares)		0.0	0.3
Ending Balance at Mar. 31, 2023	3,667.7	$ 293.7	$ (2,655.0)	394.0	5,661.2	(26.2)
Ending Balance (in shares) at Mar. 31, 2023		293.7	(49.5)
Beginning Balance at Dec. 31, 2022	3,489.9	$ 293.7	$ (2,665.3)	366.2	5,524.6	(29.3)
Beginning Balance (in shares) at Dec. 31, 2022		293.7	(49.8)
Net income	424.4
Other comprehensive income (loss)	1.5
Ending Balance at Jun. 30, 2023	3,911.0	$ 293.7	$ (2,592.8)	422.6	5,815.3	(27.8)
Ending Balance (in shares) at Jun. 30, 2023		293.7	(47.7)
Beginning Balance at Mar. 31, 2023	3,667.7	$ 293.7	$ (2,655.0)	394.0	5,661.2	(26.2)
Beginning Balance (in shares) at Mar. 31, 2023		293.7	(49.5)
Net income	221.2	$ 0.0	$ 0.0	0.0	221.2	0.0
Other comprehensive income (loss)	(1.6)	0.0	0.0	0.0	0.0	(1.6)
Cash dividends	(66.7)	0.0	0.0	0.0	(66.7)	0.0
Stock based compensation expense and stock option plan transactions	90.4	$ 0.0	$ 62.2	28.6	(0.4)	0.0
Stock based compensation expense and stock option plan transactions (in shares)		0.0	1.8
Ending Balance at Jun. 30, 2023	3,911.0	$ 293.7	$ (2,592.8)	422.6	5,815.3	(27.8)
Ending Balance (in shares) at Jun. 30, 2023		293.7	(47.7)
Beginning Balance at Dec. 31, 2023	3,855.4	$ 293.7	$ (2,878.2)	454.8	6,012.3	(27.2)
Beginning Balance (in shares) at Dec. 31, 2023		293.7	(50.6)
Net income	227.7	$ 0.0	$ 0.0	0.0	227.7	0.0
Other comprehensive income (loss)	(2.1)	0.0	0.0	0.0	0.0	(2.1)
Cash dividends	(69.0)	0.0	0.0	0.0	(69.0)	0.0
Stock based compensation expense and stock option plan transactions	88.7	$ 0.0	$ 45.4	43.5	(0.2)	0.0
Stock based compensation expense and stock option plan transactions (in shares)		0.0	1.4
Ending Balance at Mar. 31, 2024	4,100.7	$ 293.7	$ (2,832.8)	498.3	6,170.8	(29.3)
Ending Balance (in shares) at Mar. 31, 2024		293.7	(49.2)
Beginning Balance at Dec. 31, 2023	3,855.4	$ 293.7	$ (2,878.2)	454.8	6,012.3	(27.2)
Beginning Balance (in shares) at Dec. 31, 2023		293.7	(50.6)
Net income	471.2
Other comprehensive income (loss)	(1.9)
Ending Balance at Jun. 30, 2024	4,305.5	$ 293.7	$ (2,823.0)	518.7	6,345.2	(29.1)
Ending Balance (in shares) at Jun. 30, 2024		293.7	(48.9)
Beginning Balance at Mar. 31, 2024	4,100.7	$ 293.7	$ (2,832.8)	498.3	6,170.8	(29.3)
Beginning Balance (in shares) at Mar. 31, 2024		293.7	(49.2)
Net income	243.5	$ 0.0	$ 0.0	0.0	243.5	0.0
Other comprehensive income (loss)	0.2	0.0	0.0	0.0	0.0	0.2
Cash dividends	(69.2)	0.0	0.0	0.0	(69.2)	0.0
Stock based compensation expense and stock option plan transactions	30.3	$ 0.0	$ 9.8	20.4	0.1	0.0
Stock based compensation expense and stock option plan transactions (in shares)		0.0	0.3
Ending Balance at Jun. 30, 2024	$ 4,305.5	$ 293.7	$ (2,823.0)	$ 518.7	$ 6,345.2	$ (29.1)
Ending Balance (in shares) at Jun. 30, 2024		293.7	(48.9)