DERIVATIVES (Derivatives Not Designated in Hedge Relationships) (Details) - Not designated as hedging instrument - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	$ 65,286,373	$ 52,726,058
Asset derivatives Fair value	1,394,960	527,300
Liability derivatives Fair value	1,346,371	478,077
Other
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	691,071	1,087,986
Asset derivatives Fair value	20,709	10,536
Liability derivatives Fair value	25,876	13,025
Foreign exchange contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	3,700,790	3,724,007
Asset derivatives Fair value	42,671	33,749
Liability derivatives Fair value	35,118	34,428
Interest rate swap agreements
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	258,747	1,290,560
Asset derivatives Fair value	0	0
Liability derivatives Fair value	17,797	11,626
Interest rate cap agreements
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	10,894,523	9,379,720
Asset derivatives Fair value	6,461	62,552
Liability derivatives Fair value	0	0
Options for interest rate cap agreements
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	10,894,523	9,379,720
Asset derivatives Fair value	0	0
Liability derivatives Fair value	6,461	62,552
Mortgage banking derivatives
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	1,492,363	1,130,417
Asset derivatives Fair value	63,855	18,194
Liability derivatives Fair value	22,216	2,907
Mortgage banking derivatives | Forward commitments to sell loans
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	549,805	452,994
Asset derivatives Fair value	51	18
Liability derivatives Fair value	3,483	360
Mortgage banking derivatives | Interest rate lock commitments
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	322,558	167,423
Asset derivatives Fair value	16,435	3,042
Liability derivatives Fair value	0	0
Mortgage banking derivatives | Mortgage servicing
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	620,000	510,000
Asset derivatives Fair value	47,369	15,134
Liability derivatives Fair value	18,733	2,547
Customer-related derivatives
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	37,354,356	26,733,648
Asset derivatives Fair value	1,261,264	402,269
Liability derivatives Fair value	1,238,903	353,539
Customer-related derivatives | Swaps receive fixed
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	16,635,322	11,225,376
Asset derivatives Fair value	1,251,458	375,541
Liability derivatives Fair value	397	12,330
Customer-related derivatives | Swaps pay fixed
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	17,081,403	11,975,313
Asset derivatives Fair value	2,299	23,271
Liability derivatives Fair value	1,223,746	336,361
Customer-related derivatives | Other
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional	3,637,631	3,532,959
Asset derivatives Fair value	7,507	3,457
Liability derivatives Fair value	$ 14,760	$ 4,848