Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Millions	Total	PREFERRED STOCK	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	TREASURY STOCK
Beginning balance at Dec. 31, 2020	$ 11,688.3	$ 884.9	$ 408.6	$ 963.6	$ 12,207.7	$ 428.0	$ (3,204.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	375.1				375.1
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)	(362.1)					(362.1)
Dividends [Abstract]
Common Stock	(151.0)				(151.0)
Preferred Stock	(16.2)				(16.2)
Stock Awards and Options Exercised	59.4			(49.5)			108.9
Stock Purchased	(135.6)						(135.6)
Ending balance at Mar. 31, 2021	11,457.9	884.9	408.6	914.1	12,415.6	65.9	(3,231.2)
Beginning balance at Dec. 31, 2021	12,016.8	884.9	408.6	939.3	13,117.3	(35.6)	(3,297.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	389.3				389.3
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)	(871.4)					(871.4)
Dividends [Abstract]
Common Stock	(147.8)				(147.8)
Preferred Stock	(16.2)				(16.2)
Stock Awards and Options Exercised	72.9			(7.6)			80.5
Stock Purchased	(33.8)						(33.8)
Ending balance at Mar. 31, 2022	$ 11,409.8	$ 884.9	$ 408.6	$ 931.7	$ 13,342.6	$ (907.0)	$ (3,251.0)