Offsetting of Assets and Liabilities (Offsetting of Derivative Assets and Securities Purchased Under Agreements to Resell) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED ASSETS	$ 3,505.1	$ 1,902.7
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,790.8	1,533.8
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	1,714.3	368.9
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	17.2	2.8
NET AMOUNT	1,697.1	366.1
Total Derivatives Not Subject to a Master Netting Arrangement
GROSS RECOGNIZED ASSETS	1,359.0	444.7
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	1,359.0	444.7
Total Derivatives
GROSS RECOGNIZED ASSETS	4,864.1	2,347.4
Derivative Assets	3,073.3	813.6
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	17.2	2.8
NET AMOUNT	3,056.1	810.8
Securities Purchased under Agreements to Resell
GROSS RECOGNIZED ASSETS	4,784.9	2,078.9
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	3,613.1	1,392.5
Securities Purchased under Agreements to Resell	1,171.8	686.4
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	1,171.8	686.4
Other assets excluding derivatives and non financial instruments	8,300.0	7,800.0
Foreign Exchange Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED ASSETS	3,402.2	1,762.7
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,739.4	1,530.7
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	1,662.8	232.0
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	17.2	2.8
NET AMOUNT	1,645.6	229.2
Interest Rate Swap Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED ASSETS	102.9	140.0
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	51.4	3.1
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	51.5	136.9
NET AMOUNT	$ 51.5	$ 136.9