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Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance, beginning of period at Dec. 31, 2016	$ 9,770.4	$ 882.0	$ 408.6	$ 1,035.8	$ 8,908.4	$ (370.0)	$ (1,094.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,199.0				1,199.0
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)	(44.3)					(44.3)
Dividends – Common Stock	(372.5)				(372.5)
Preferred Stock	(49.8)				(49.8)
Stock Options and Awards	225.1						225.1
Stock Purchased	(523.1)						(523.1)
Treasury Stock Transactions — Stock Options and Awards	(117.1)			(117.1)
Stock Options and Awards — Amortization	128.5			128.5
Balance, end of period at Dec. 31, 2017	10,216.2	882.0	408.6	1,047.2	9,685.1	(414.3)	(1,392.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income	0.0				25.3	(25.3)
Net Income	1,556.4				1,556.4
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)	(14.1)					(14.1)
Dividends – Common Stock	(439.1)				(439.1)
Preferred Stock	(46.4)				(46.4)
Stock Options and Awards	142.8						142.8
Stock Purchased	(924.3)						(924.3)
Treasury Stock Transactions — Stock Options and Awards	(110.2)			(110.2)
Stock Options and Awards — Amortization	131.5			131.5
Balance, end of period at Dec. 31, 2018	10,508.3	882.0	408.6	1,068.5	10,776.8	(453.7)	(2,173.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,492.2				1,492.2
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)	259.0					259.0
Dividends – Common Stock	(565.9)				(565.9)
Preferred Stock	(46.4)				(46.4)
Issuance of Preferred Stock, Series E	391.4	391.4
Stock Options and Awards	208.0						208.0
Stock Purchased	(1,100.2)						(1,100.2)
Treasury Stock Transactions — Stock Options and Awards	(163.9)			(163.9)
Stock Options and Awards — Amortization	108.5			108.5
Balance, end of period at Dec. 31, 2019	$ 11,091.0	$ 1,273.4	$ 408.6	$ 1,013.1	$ 11,656.7	$ (194.7)	$ (3,066.1)