DERIVATIVES ACTIVITIES - Derivative Notionals (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Hedging instruments under ASC 815
Derivatives
Derivative notionals	$ 420,823	$ 376,831
Hedging instruments under ASC 815 | Interest rate contracts
Derivatives
Derivative notionals	318,089	273,636
Hedging instruments under ASC 815 | Interest rate swaps
Derivatives
Derivative notionals	318,089	273,636
Hedging instruments under ASC 815 | Interest rate futures and forwards
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Interest rate contract options | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Interest rate contract options | Purchased
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Foreign exchange contracts
Derivatives
Derivative notionals	101,539	102,393
Hedging instruments under ASC 815 | Foreign exchange swaps
Derivatives
Derivative notionals	63,104	57,153
Hedging instruments under ASC 815 | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	38,275	41,410
Hedging instruments under ASC 815 | Foreign exchange contract options | Written or Sold
Derivatives
Derivative notionals	80	1,726
Hedging instruments under ASC 815 | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	80	2,104
Hedging instruments under ASC 815 | Equity contracts
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity swaps
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity futures and forwards
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity contract options | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity contract options | Purchased
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other contracts
Derivatives
Derivative notionals	1,195	802
Hedging instruments under ASC 815 | Commodity and other swaps
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other futures and forwards
Derivatives
Derivative notionals	1,195	802
Hedging instruments under ASC 815 | Commodity and other contract options | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other contract options | Purchased
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Credit derivatives
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Credit derivatives | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Credit derivatives | Purchased
Derivatives
Derivative notionals	0	0
Other derivative instruments, Trading derivatives
Derivatives
Derivative notionals	39,522,192	46,221,407
Other derivative instruments, Trading derivatives | Interest rate contracts
Derivatives
Derivative notionals	24,672,211	28,321,891
Other derivative instruments, Trading derivatives | Interest rate swaps
Derivatives
Derivative notionals	17,063,272	18,138,686
Other derivative instruments, Trading derivatives | Interest rate futures and forwards
Derivatives
Derivative notionals	3,636,658	4,632,257
Other derivative instruments, Trading derivatives | Interest rate contract options | Written or Sold
Derivatives
Derivative notionals	2,114,511	3,018,469
Other derivative instruments, Trading derivatives | Interest rate contract options | Purchased
Derivatives
Derivative notionals	1,857,770	2,532,479
Other derivative instruments, Trading derivatives | Foreign exchange contracts
Derivatives
Derivative notionals	11,910,251	14,963,895
Other derivative instruments, Trading derivatives | Foreign exchange swaps
Derivatives
Derivative notionals	6,063,853	6,738,158
Other derivative instruments, Trading derivatives | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	3,979,188	5,115,504
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Written or Sold
Derivatives
Derivative notionals	908,061	1,566,717
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	959,149	1,543,516
Other derivative instruments, Trading derivatives | Equity contracts
Derivatives
Derivative notionals	1,247,562	1,065,326
Other derivative instruments, Trading derivatives | Equity swaps
Derivatives
Derivative notionals	197,893	217,580
Other derivative instruments, Trading derivatives | Equity futures and forwards
Derivatives
Derivative notionals	66,705	52,053
Other derivative instruments, Trading derivatives | Equity contract options | Written or Sold
Derivatives
Derivative notionals	560,571	454,675
Other derivative instruments, Trading derivatives | Equity contract options | Purchased
Derivatives
Derivative notionals	422,393	341,018
Other derivative instruments, Trading derivatives | Commodity and other contracts
Derivatives
Derivative notionals	384,855	349,707
Other derivative instruments, Trading derivatives | Commodity and other swaps
Derivatives
Derivative notionals	69,445	79,133
Other derivative instruments, Trading derivatives | Commodity and other futures and forwards
Derivatives
Derivative notionals	137,192	146,647
Other derivative instruments, Trading derivatives | Commodity and other contract options | Written or Sold
Derivatives
Derivative notionals	91,587	62,629
Other derivative instruments, Trading derivatives | Commodity and other contract options | Purchased
Derivatives
Derivative notionals	86,631	61,298
Other derivative instruments, Trading derivatives | Credit derivatives
Derivatives
Derivative notionals	1,307,313	1,520,588
Other derivative instruments, Trading derivatives | Credit derivatives | Written or Sold
Derivatives
Derivative notionals	603,387	724,939
Other derivative instruments, Trading derivatives | Credit derivatives | Purchased
Derivatives
Derivative notionals	703,926	795,649
Rule Changes Adopted by Clearing Organizations
Derivatives
Reduction in derivative assets	180,000	100,000
Reduction in derivative liabilities	$ 180,000	$ 100,000