Goodwill and Other Intangibles (Other Intangible Assets and Capitalized Software) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 208.4	$ 221.3
Less: Accumulated Amortization	112.6	108.7
Net Book Value	95.8	112.6
Computer Software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,635.7	4,337.4
Less: Accumulated Amortization	3,003.2	2,744.5
Net Book Value	$ 1,632.5	$ 1,592.9