Condensed Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings
Balance at Dec. 31, 2020		$ 158.0	$ 2,137.8	$ (689.9)	$ (155.1)
Common stock repurchased and retired		0.0	0.0
Common stock issued for stock options exercised	$ 50.2	2.4	47.8
Common stock issued for other transactions		0.1	2.6
Stock-based compensation			(0.3)
Other comprehensive (loss) income	35.6			35.6
Net income	599.4				599.4
Common stock dividends paid					(63.7)
Balance at Jun. 30, 2021	2,074.7	$ 160.5	2,187.9	(654.3)	380.6
Dividends declared per share of common stock		$ 0.40
Balance at Mar. 31, 2021		$ 159.2	2,164.3	(683.7)	56.8
Common stock repurchased and retired		0.0	0.0
Common stock issued for stock options exercised		1.2	23.3
Common stock issued for other transactions		0.1	1.2
Stock-based compensation			(0.9)
Other comprehensive (loss) income	29.4			29.4
Net income	355.8				355.8
Common stock dividends paid					(32.0)
Balance at Jun. 30, 2021	2,074.7	$ 160.5	2,187.9	(654.3)	380.6
Dividends declared per share of common stock		$ 0.20
Balance at Dec. 31, 2021	2,652.2	$ 156.8	1,969.6	(488.0)	1,013.8
Common stock repurchased and retired	(689.7)	(12.6)	(677.1)
Common stock issued for stock options exercised	20.9	0.9	20.0
Common stock issued for other transactions		0.0	3.0
Stock-based compensation			3.0
Other comprehensive (loss) income	(47.5)			(47.5)
Net income	815.1				815.1
Common stock dividends paid					(60.9)
Balance at Jun. 30, 2022	2,696.1	$ 145.1	1,318.5	(535.5)	1,768.0
Dividends declared per share of common stock		$ 0.40
Balance at Mar. 31, 2022		$ 151.8	1,719.3	(461.2)	1,376.0
Common stock repurchased and retired		(7.4)	(419.1)
Common stock issued for stock options exercised		0.7	15.0
Common stock issued for other transactions		0.0	0.8
Stock-based compensation			2.5
Other comprehensive (loss) income	(74.3)			(74.3)
Net income	422.1				422.1
Common stock dividends paid					(30.1)
Balance at Jun. 30, 2022	$ 2,696.1	$ 145.1	$ 1,318.5	$ (535.5)	$ 1,768.0
Dividends declared per share of common stock		$ 0.20