Offsetting of Assets and Liabilities (Offsetting of Derivative Liabilities and Securities Sold Under Agreements to Repurchase) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	$ 2,076.7	$ 2,548.9
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,461.0	1,865.9
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	615.7	683.0
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Net Amount	615.7	683.0
Total Derivatives Not Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	530.4	1,105.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0
NET AMOUNT	530.4	1,105.2
Offsetting Derivative Liabilities [Abstract]
GROSS RECOGNIZED LIABILITIES	2,607.1	3,654.1
Derivative Liabilities	1,146.1	1,788.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	1,146.1	1,788.2
Securities Sold under Agreements to Repurchase(2)
GROSS RECOGNIZED LIABILITIES	35,520.4	11,991.1
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	34,532.3	11,423.9
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	988.1	567.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	988.1	567.2
Other liabilities	3,300.0	3,200.0
Foreign Exchange Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	1,632.2	2,082.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,422.1	1,826.7
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	210.1	255.6
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Net Amount	210.1	255.6
Interest Rate Swap Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	408.1	426.5
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	4.1	5.9
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	404.0	420.6
Net Amount	404.0	420.6
Interest Rate Swap Contracts | Interest Rate Swaps Exchange Cleared
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES		5.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET		0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET		5.3
Net Amount		5.3
Other Financial Derivatives | Other Financial Derivatives
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	36.4	34.8
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	34.8	33.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	1.6	1.5
Net Amount	$ 1.6	$ 1.5