Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	COMMON STOCK, $1 PAR VALUE:	ADDITIONAL PAID-IN CAPITAL:	TREASURY STOCK, AT COST:	RETAINED EARNINGS:	RETAINED EARNINGS: Cumulative Effect, Period of Adoption, Adjustment	ACCUMULATED OTHER COMPREHENSIVE LOSS:
Beginning balance at Dec. 31, 2017		$ 351.8	$ 123.2		$ 8,369.1		$ (793.6)
Net income	$ 2,195.1				2,195.1
Purchases, shares: 2020 - .71; 2019 - 1.68; 2018 - 5.85				$ (354.4)
Cash dividends declared on common stock,per share: 2020 - $1.98; 2019 - $3.58; 2018 - $3.09					(1,078.8)
Treasury stock retirement		(5.8)	(88.3)	354.4	(260.3)
Stock compensation		0.6
Stock compensation and tax benefit			34.5
Other comprehensive income (loss)	(271.7)						(271.7)
Reclassifications to retained earnings in accordance with ASU 2018-02							(33.2)
Ending balance at Dec. 31, 2018	8,592.9	346.6	69.4		9,275.4	$ 50.3	(1,098.5)
Net income	2,387.9				2,387.9
Purchases, shares: 2020 - .71; 2019 - 1.68; 2018 - 5.85				(110.2)
Cash dividends declared on common stock,per share: 2020 - $1.98; 2019 - $3.58; 2018 - $3.09					(1,242.0)
Treasury stock retirement		(1.7)	(85.7)	110.2	(22.8)
Stock compensation		1.4
Stock compensation and tax benefit			77.7
Other comprehensive income (loss)	(1.6)						(1.6)
Ending balance at Dec. 31, 2019	9,706.1	346.3	61.4		10,398.5		(1,100.1)
Net income	1,298.4				1,298.4
Purchases, shares: 2020 - .71; 2019 - 1.68; 2018 - 5.85				(42.1)
Cash dividends declared on common stock,per share: 2020 - $1.98; 2019 - $3.58; 2018 - $3.09					(687.1)
Treasury stock retirement		(0.7)	(41.4)	$ 42.1
Stock compensation		1.0
Stock compensation and tax benefit			68.5
Other comprehensive income (loss)	49.8						49.8
Ending balance at Dec. 31, 2020	$ 10,390.0	$ 346.6	$ 88.5		$ 11,005.2	$ (4.6)	$ (1,050.3)