Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net Income	$ 298.4	$ 257.6	$ 842.4	$ 766.0
Other Comprehensive Income (Loss) (Net of Tax and Reclassifications)
Net Unrealized (Losses) Gains on Securities Available for Sale	(2.2)	(13.9)	18.7	94.3
Net Unrealized (Losses) Gains on Cash Flow Hedges	(1.9)	0.0	(4.9)	6.6
Foreign Currency Translation Adjustments	3.6	(9.5)	10.5	0.7
Pension and Other Postretirement Benefit Adjustments	4.3	3.3	10.6	11.4
Other Comprehensive Income	3.8	(20.1)	34.9	113.0
Comprehensive Income	$ 302.2	$ 237.5	$ 877.3	$ 879.0

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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