DERIVATIVES - Derivative Notionals (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Hedging instruments under ASC 815
Derivatives
Derivative notionals	$ 455,146	$ 420,823
Hedging instruments under ASC 815 | Interest rate contracts
Derivatives
Derivative notionals	346,007	318,089
Hedging instruments under ASC 815 | Interest rate swaps
Derivatives
Derivative notionals	346,007	318,089
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	108,645	101,539
Hedging instruments under ASC 815 | Foreign exchange swaps
Derivatives
Derivative notionals	66,733	63,104
Hedging instruments under ASC 815 | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	38,997	38,275
Hedging instruments under ASC 815 | Foreign exchange contract options | Written or Sold
Derivatives
Derivative notionals	1,428	80
Hedging instruments under ASC 815 | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	1,487	80
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	494	1,195
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	494	1,195
Hedging instruments under ASC 815 | Commodity and other contracts | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other contracts | 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	40,290,775	39,522,192
Other derivative instruments, Trading derivatives | Interest rate contracts
Derivatives
Derivative notionals	25,240,217	24,672,211
Other derivative instruments, Trading derivatives | Interest rate swaps
Derivatives
Derivative notionals	17,622,599	17,063,272
Other derivative instruments, Trading derivatives | Interest rate futures and forwards
Derivatives
Derivative notionals	4,449,386	3,636,658
Other derivative instruments, Trading derivatives | Interest rate contract options | Written or Sold
Derivatives
Derivative notionals	1,674,348	2,114,511
Other derivative instruments, Trading derivatives | Interest rate contract options | Purchased
Derivatives
Derivative notionals	1,493,884	1,857,770
Other derivative instruments, Trading derivatives | Foreign exchange contracts
Derivatives
Derivative notionals	12,348,614	11,910,251
Other derivative instruments, Trading derivatives | Foreign exchange swaps
Derivatives
Derivative notionals	6,150,239	6,063,853
Other derivative instruments, Trading derivatives | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	4,241,268	3,979,188
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Written or Sold
Derivatives
Derivative notionals	972,083	908,061
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	985,024	959,149
Other derivative instruments, Trading derivatives | Equity contracts
Derivatives
Derivative notionals	1,060,467	1,247,562
Other derivative instruments, Trading derivatives | Equity swaps
Derivatives
Derivative notionals	201,655	197,893
Other derivative instruments, Trading derivatives | Equity futures and forwards
Derivatives
Derivative notionals	76,743	66,705
Other derivative instruments, Trading derivatives | Equity contract options | Written or Sold
Derivatives
Derivative notionals	449,807	560,571
Other derivative instruments, Trading derivatives | Equity contract options | Purchased
Derivatives
Derivative notionals	332,262	422,393
Other derivative instruments, Trading derivatives | Commodity and other contracts
Derivatives
Derivative notionals	422,572	384,855
Other derivative instruments, Trading derivatives | Commodity and other swaps
Derivatives
Derivative notionals	77,244	69,445
Other derivative instruments, Trading derivatives | Commodity and other futures and forwards
Derivatives
Derivative notionals	153,421	137,192
Other derivative instruments, Trading derivatives | Commodity and other contracts | Written or Sold
Derivatives
Derivative notionals	97,406	91,587
Other derivative instruments, Trading derivatives | Commodity and other contracts | Purchased
Derivatives
Derivative notionals	94,501	86,631
Other derivative instruments, Trading derivatives | Credit derivatives
Derivatives
Derivative notionals	1,218,905	1,307,313
Other derivative instruments, Trading derivatives | Credit derivatives | Written or Sold
Derivatives
Derivative notionals	574,692	603,387
Other derivative instruments, Trading derivatives | Credit derivatives | Purchased
Derivatives
Derivative notionals	644,213	703,926
Rule Changes Adopted by Clearing Organizations
Derivatives
Reduction in derivative receivables	$ 290,000	$ 180,000