DERIVATIVES - Derivative Notionals (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Hedging instruments under ASC 815
Derivatives
Derivative notionals	$ 449,492	$ 420,823
Hedging instruments under ASC 815 | Interest rate contracts
Derivatives
Derivative notionals	347,587	318,089
Hedging instruments under ASC 815 | Interest rate swaps
Derivatives
Derivative notionals	347,587	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
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	101,121	101,539
Hedging instruments under ASC 815 | Foreign exchange swaps
Derivatives
Derivative notionals	64,986	63,104
Hedging instruments under ASC 815 | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	34,616	38,275
Hedging instruments under ASC 815 | Foreign exchange contract options | Written
Derivatives
Derivative notionals	753	80
Hedging instruments under ASC 815 | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	766	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
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	784	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	784	1,195
Hedging instruments under ASC 815 | Commodity and other contracts | Written
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
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	40,943,493	39,522,192
Other derivative instruments, Trading derivatives | Interest rate contracts
Derivatives
Derivative notionals	25,624,242	24,672,211
Other derivative instruments, Trading derivatives | Interest rate swaps
Derivatives
Derivative notionals	17,709,922	17,063,272
Other derivative instruments, Trading derivatives | Interest rate futures and forwards
Derivatives
Derivative notionals	4,894,587	3,636,658
Other derivative instruments, Trading derivatives | Interest rate contract options | Written
Derivatives
Derivative notionals	1,590,805	2,114,511
Other derivative instruments, Trading derivatives | Interest rate contract options | Purchased
Derivatives
Derivative notionals	1,428,928	1,857,770
Other derivative instruments, Trading derivatives | Foreign exchange contracts
Derivatives
Derivative notionals	12,342,701	11,910,251
Other derivative instruments, Trading derivatives | Foreign exchange swaps
Derivatives
Derivative notionals	6,104,059	6,063,853
Other derivative instruments, Trading derivatives | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	4,275,082	3,979,188
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Written
Derivatives
Derivative notionals	981,562	908,061
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	981,998	959,149
Other derivative instruments, Trading derivatives | Equity contracts
Derivatives
Derivative notionals	1,223,638	1,247,562
Other derivative instruments, Trading derivatives | Equity swaps
Derivatives
Derivative notionals	237,127	197,893
Other derivative instruments, Trading derivatives | Equity futures and forwards
Derivatives
Derivative notionals	67,470	66,705
Other derivative instruments, Trading derivatives | Equity contract options | Written
Derivatives
Derivative notionals	525,911	560,571
Other derivative instruments, Trading derivatives | Equity contract options | Purchased
Derivatives
Derivative notionals	393,130	422,393
Other derivative instruments, Trading derivatives | Commodity and other contracts
Derivatives
Derivative notionals	431,905	384,855
Other derivative instruments, Trading derivatives | Commodity and other swaps
Derivatives
Derivative notionals	79,079	69,445
Other derivative instruments, Trading derivatives | Commodity and other futures and forwards
Derivatives
Derivative notionals	163,925	137,192
Other derivative instruments, Trading derivatives | Commodity and other contracts | Written
Derivatives
Derivative notionals	95,573	91,587
Other derivative instruments, Trading derivatives | Commodity and other contracts | Purchased
Derivatives
Derivative notionals	93,328	86,631
Other derivative instruments, Trading derivatives | Credit derivatives
Derivatives
Derivative notionals	1,321,007	1,307,313
Other derivative instruments, Trading derivatives | Credit derivatives | Written
Derivatives
Derivative notionals	621,099	603,387
Other derivative instruments, Trading derivatives | Credit derivatives | Purchased
Derivatives
Derivative notionals	699,908	703,926
Rule Changes Adopted by Clearing Organizations
Derivatives
Reduction in derivative receivables	$ 270,000	$ 180,000