Offsetting of Assets and Liabilities (Offsetting of Derivative Liabilities and Securities Sold Under Agreements to Repurchase) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	$ 1,566.5	$ 3,738.0
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,283.5	2,817.1
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	283.0	920.9
Gross amounts not offset in the balance sheet	0.0	0.5
Net Amount	283.0	920.4
Total Derivatives Not Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	568.7	1,144.8
NET AMOUNT	568.7	1,144.8
Total Derivatives
GROSS RECOGNIZED LIABILITIES	2,135.2	4,882.8
Derivative Liabilities	851.7	2,065.7
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.5
Net Amount	851.7	2,065.2
Securities Sold under Agreements to Repurchase
GROSS RECOGNIZED LIABILITIES	1,924.4	39.8
Gross amounts offset in the balance sheet	1,392.5
Securities Sold Under Agreements to Repurchase	531.9	39.8
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	531.9	39.8
Other liabilities	3,300.0	3,500.0
Foreign Exchange Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	1,430.1	3,577.7
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,234.5	2,718.6
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	195.6	859.1
Gross amounts not offset in the balance sheet	0.0	0.5
Net Amount	195.6	858.6
Interest Rate Swaps | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	98.7	125.0
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	48.1	98.5
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	50.6	26.5
Net Amount	50.6	26.5
Interest Rate Swaps | Interest Rate Swaps Exchange Cleared
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	0.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	0.2
Net Amount	0.2
Other Financial Derivatives | Other Financial Derivatives
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	37.5	35.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	0.9	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	36.6	35.3
Net Amount	$ 36.6	$ 35.3