Statements of Consolidated Shareholders' Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Other Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment
Beginning balance at Dec. 31, 2018	$ 3,730.7		$ 118.4	$ 2,896.4	$ 6,246.5		$ (4,900.7)	$ (629.9)	$ (8.3)
Beginning balance (ASU 2016-02) at Dec. 31, 2018		$ (8.4)				$ (8.4)
Beginning balance (ASU 2018-02) at Dec. 31, 2018		0.0				8.3			$ (8.3)
Shareholders' Equity [Roll Forward]
Net income	1,541.3				1,541.3
Other comprehensive income	(41.3)							(41.3)
Treasury stock purchased	(778.8)						(778.8)
Treasury stock transferred from defined benefit pension plan	(131.8)						(131.8)
Stock-based compensation activity	230.3		1.0	254.5			(25.2)
Other adjustments	2.1			2.1
Cash dividends	(420.8)				(420.8)
Ending balance at Dec. 31, 2019	4,123.3	$ (3.0)	119.4	3,153.0	7,366.9	$ (3.0)	(5,836.5)	(679.5)
Shareholders' Equity [Roll Forward]
Net income	2,030.4				2,030.4
Other comprehensive income	(38.8)							(38.8)
Treasury stock purchased	(2,446.3)						(2,446.3)
Stock-based compensation activity	250.8		1.1	276.4			(26.7)
Treasury stock issued	182.4			61.6			120.8
Treasury stock retired	0.0		(30.6)		(8,061.6)		8,092.2
Other adjustments	0.0			0.4	(0.4)
Cash dividends	(488.0)				(488.0)
Ending balance at Dec. 31, 2020	3,610.8		89.9	3,491.4	844.3		(96.5)	(718.3)
Shareholders' Equity [Roll Forward]
Net income	1,864.4				1,864.4
Other comprehensive income	19.9							19.9
Treasury stock purchased	(2,752.3)						(2,752.3)
Stock-based compensation activity	268.3		0.9	290.9			(23.5)
Treasury stock issued	11.7			9.3			2.4
Other adjustments	1.5			1.4	0.1
Cash dividends	(587.1)				(587.1)
Ending balance at Dec. 31, 2021	$ 2,437.2		$ 90.8	$ 3,793.0	$ 2,121.7		$ (2,869.9)	$ (698.4)