Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss
Balance at beginning of period at Dec. 31, 2021		$ 5.8	$ 96.2	$ 2,970.9	$ (30.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised			7.8
Purchases of common stock			(105.6)	(39.0)
Stock-based compensation			4.4
Net earnings	$ 841.3			841.3
Cash dividends paid				(534.4)
Translation adjustment upon merger of foreign subsidiary				0.9
Other comprehensive loss					(56.4)
Balance at end of period at Sep. 30, 2022	$ 3,161.2	5.8	2.8	3,239.7	(87.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends paid per share of common stock (in dollars per share)	$ 0.93
Balance at beginning of period at Dec. 31, 2021		5.8	96.2	2,970.9	(30.7)
Balance at end of period at Dec. 31, 2022	$ 3,163.2	5.7	3.6	3,218.7	(64.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends paid per share of common stock (in dollars per share)	$ 1.24
Balance at beginning of period at Jun. 30, 2022		5.8	55.7	3,171.6	(54.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised			2.0
Purchases of common stock			(56.3)	(39.0)
Stock-based compensation			1.4
Net earnings	$ 284.6			284.6
Cash dividends paid				(177.5)
Translation adjustment upon merger of foreign subsidiary				0.0
Other comprehensive loss					(32.7)
Balance at end of period at Sep. 30, 2022	$ 3,161.2	5.8	2.8	3,239.7	(87.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends paid per share of common stock (in dollars per share)	$ 0.31
Balance at end of period at Dec. 31, 2022	$ 3,163.2	5.7	3.6	3,218.7	(64.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends paid per share of common stock (in dollars per share)	$ 0.31
Stock options exercised			15.4
Purchases of common stock			0.0	0.0
Stock-based compensation			5.6
Net earnings	$ 888.6			888.6
Cash dividends paid				(599.5)
Translation adjustment upon merger of foreign subsidiary				0.0
Other comprehensive loss					(6.7)
Balance at end of period at Sep. 30, 2023	$ 3,466.6	5.7	24.6	3,507.8	(71.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends paid per share of common stock (in dollars per share)	$ 1.05
Balance at beginning of period at Jun. 30, 2023		5.7	19.9	3,412.1	(56.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised			2.9
Purchases of common stock			0.0	0.0
Stock-based compensation			1.8
Net earnings	$ 295.5			295.5
Cash dividends paid				(199.8)
Translation adjustment upon merger of foreign subsidiary				0.0
Other comprehensive loss					(14.6)
Balance at end of period at Sep. 30, 2023	$ 3,466.6	$ 5.7	$ 24.6	$ 3,507.8	$ (71.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends paid per share of common stock (in dollars per share)	$ 0.35