Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 294.5	$ 384.6	$ 968.4	$ 1,121.1
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)
Net Unrealized Gains on Debt Securities Available for Sale	33.5	57.0	551.3	305.0
Net Unrealized Gains (Losses) on Cash Flow Hedges	1.3	(2.4)	5.3	(1.9)
Net Foreign Currency Adjustments	1.8	9.9	29.5	38.8
Net Pension and Other Postretirement Benefit Adjustments	17.5	4.3	33.1	20.8
Net Change	54.1	68.8	619.2	362.7
Comprehensive Income	$ 348.6	$ 453.4	$ 1,587.6	$ 1,483.8