CONCENTRATIONS OF CREDIT RISK (Details) - Total investments - Geographic - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
U.S.
Concentration Risk [Line Items]
Credit exposure from investment securities, loans and trading assets	$ 250.0	$ 227.8
GERMANY
Concentration Risk [Line Items]
Credit exposure from investment securities, loans and trading assets	46.4	38.3
JAPAN
Concentration Risk [Line Items]
Credit exposure from investment securities, loans and trading assets	28.8	25.8
State and Municipalities
Concentration Risk [Line Items]
Credit exposure from investment securities, loans and trading assets	$ 27.9	$ 30.6