Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Mar. 01, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Entity Information [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 146.1	$ 129.1			$ 73.0	$ 74.2	$ 72.4	$ 73.0
Off-Balance Sheet, Credit Loss, Liability					0.0
Credit Extension Commitments	2,228.8				2,067.0
Unused Credit Card Lines
Entity Information [Line Items]
Credit Extension Commitments	692.5				671.8
Standby Letter of Credit
Entity Information [Line Items]
Credit Extension Commitments	55.7				42.7
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Entity Information [Line Items]
Accounts Receivable, Allowance for Credit Loss		2.1		$ 103.0	0.0		0.0	0.0
Off-Balance Sheet, Credit Loss, Liability	2.3	0.2	$ 0.0	2.3	0.0	$ 0.0	$ 0.0	$ 0.0
Cumulative Effect, Period of Adoption, Adjustment
Entity Information [Line Items]
Accounts Receivable, Allowance for Credit Loss	30.0			30.0
Off-Balance Sheet, Credit Loss, Liability				$ 2.3
Agricultural
Entity Information [Line Items]
Accounts Receivable, Allowance for Credit Loss	0.9	$ 1.1			$ 1.6
Agricultural | Cumulative Effect, Period of Adoption, Adjustment
Entity Information [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ (0.6)