Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income Cumulative Effect of Adjustment [Member]	Retained Earnings	Retained Earnings Cumulative Effect of Adjustment [Member]	Treasury Stock	Non- controlling Interests
Beginning Balance at Dec. 31, 2018	$ 2,180.0	$ 1.8	$ 2,766.0	$ (67.0)		$ 1,448.1		$ (1,970.7)	$ 1.8
Comprehensive income:
Net income	431.3					431.9			(0.6)
Other comprehensive income (loss)	3.0			3.0
Stock options exercised	17.3		17.3
Stock-based compensation	21.8		30.5					(8.7)
Adoption of ASU 2018-02 | ASU 2018-02 [Member]					$ (8.6)		$ 8.6
Treasury stock purchase	(100.0)							(100.0)
Dividends	(125.6)					(125.6)
Ending Balance at Dec. 31, 2019	2,427.8	1.8	2,813.8	(72.6)		1,763.0		(2,079.4)	1.2
Comprehensive income:
Net income	554.4					553.1			1.3
Other comprehensive income (loss)	17.5			17.5
Stock options exercised	64.9		64.9
Stock-based compensation	36.9		47.6					(10.7)
Treasury stock purchase	(187.6)							(187.6)
Dividends to non-controlling interest	(2.5)								$ (2.5)
Dividends	(135.9)					(135.9)
Ending Balance at Dec. 31, 2020	2,775.5	1.8	2,926.3	(55.1)		2,180.2		(2,277.7)
Comprehensive income:
Net income	772.4					772.4
Other comprehensive income (loss)	30.5			30.5
Stock options exercised	41.9	0.1	41.8
Stock-based compensation	36.9		50.2					(13.3)
Treasury stock purchase	(447.7)							(447.7)
Dividends	(144.7)					(144.7)
Ending Balance at Dec. 31, 2021	$ 3,064.8	$ 1.9	$ 3,018.3	$ (24.6)		$ 2,807.9		$ (2,738.7)