DERIVATIVES - Derivative Notionals (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Hedging instruments under ASC 815
Derivatives
Derivative notionals	$ 395,224	$ 438,164
Hedging instruments under ASC 815 | Interest rate contracts
Derivatives
Derivative notionals	295,160	334,351
Hedging instruments under ASC 815 | Interest rate swaps
Derivatives
Derivative notionals	295,160	334,351
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	98,135	102,889
Hedging instruments under ASC 815 | Foreign exchange swaps
Derivatives
Derivative notionals	55,575	65,709
Hedging instruments under ASC 815 | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	42,510	37,080
Hedging instruments under ASC 815 | Foreign exchange contract options | Written
Derivatives
Derivative notionals	24	47
Hedging instruments under ASC 815 | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	26	53
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	1,929	924
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	1,929	924
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	42,688,843	39,808,290
Other derivative instruments, Trading derivatives | Interest rate contracts
Derivatives
Derivative notionals	27,081,888	24,858,399
Other derivative instruments, Trading derivatives | Interest rate swaps
Derivatives
Derivative notionals	19,629,538	17,724,147
Other derivative instruments, Trading derivatives | Interest rate futures and forwards
Derivatives
Derivative notionals	4,381,531	4,142,514
Other derivative instruments, Trading derivatives | Interest rate contract options | Written
Derivatives
Derivative notionals	1,598,478	1,573,483
Other derivative instruments, Trading derivatives | Interest rate contract options | Purchased
Derivatives
Derivative notionals	1,472,341	1,418,255
Other derivative instruments, Trading derivatives | Foreign exchange contracts
Derivatives
Derivative notionals	12,668,170	12,320,659
Other derivative instruments, Trading derivatives | Foreign exchange swaps
Derivatives
Derivative notionals	6,495,324	6,567,304
Other derivative instruments, Trading derivatives | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	4,586,090	3,945,391
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Written
Derivatives
Derivative notionals	796,584	907,338
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	790,172	900,626
Other derivative instruments, Trading derivatives | Equity contracts
Derivatives
Derivative notionals	1,350,747	1,110,328
Other derivative instruments, Trading derivatives | Equity swaps
Derivatives
Derivative notionals	306,856	274,098
Other derivative instruments, Trading derivatives | Equity futures and forwards
Derivatives
Derivative notionals	82,175	67,025
Other derivative instruments, Trading derivatives | Equity contract options | Written
Derivatives
Derivative notionals	525,671	441,003
Other derivative instruments, Trading derivatives | Equity contract options | Purchased
Derivatives
Derivative notionals	436,045	328,202
Other derivative instruments, Trading derivatives | Commodity and other contracts
Derivatives
Derivative notionals	391,691	362,527
Other derivative instruments, Trading derivatives | Commodity and other swaps
Derivatives
Derivative notionals	90,785	80,127
Other derivative instruments, Trading derivatives | Commodity and other futures and forwards
Derivatives
Derivative notionals	168,072	143,175
Other derivative instruments, Trading derivatives | Commodity and other contracts | Written
Derivatives
Derivative notionals	68,024	71,376
Other derivative instruments, Trading derivatives | Commodity and other contracts | Purchased
Derivatives
Derivative notionals	64,810	67,849
Other derivative instruments, Trading derivatives | Credit derivatives
Derivatives
Derivative notionals	1,196,347	1,156,377
Other derivative instruments, Trading derivatives | Credit derivatives | Written
Derivatives
Derivative notionals	563,906	543,607
Other derivative instruments, Trading derivatives | Credit derivatives | Purchased
Derivatives
Derivative notionals	632,441	612,770
Rule Changes Adopted by Clearing Organizations
Derivatives
Reduction in derivative receivables	$ 275,000	$ 280,000