DERIVATIVES - Derivative Notionals (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Hedging instruments under ASC 815
Derivatives
Derivative notionals	$ 345,891	$ 374,383
Hedging instruments under ASC 815 | Interest rate contracts
Derivatives
Derivative notionals	257,336	277,003
Hedging instruments under ASC 815 | Interest rate swaps
Derivatives
Derivative notionals	257,336	277,003
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	85,948	95,630
Hedging instruments under ASC 815 | Foreign exchange swaps
Derivatives
Derivative notionals	36,307	45,851
Hedging instruments under ASC 815 | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	49,641	49,779
Hedging instruments under ASC 815 | Foreign exchange contract options | Written
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	0	0
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	2,607	1,750
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	2,607	1,750
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	45,780,798	41,538,477
Other derivative instruments, Trading derivatives | Interest rate contracts
Derivatives
Derivative notionals	28,426,255	25,541,413
Other derivative instruments, Trading derivatives | Interest rate swaps
Derivatives
Derivative notionals	19,320,033	17,077,712
Other derivative instruments, Trading derivatives | Interest rate futures and forwards
Derivatives
Derivative notionals	3,909,064	3,022,127
Other derivative instruments, Trading derivatives | Interest rate contract options | Written
Derivatives
Derivative notionals	2,631,715	2,753,912
Other derivative instruments, Trading derivatives | Interest rate contract options | Purchased
Derivatives
Derivative notionals	2,565,443	2,687,662
Other derivative instruments, Trading derivatives | Foreign exchange contracts
Derivatives
Derivative notionals	14,560,747	13,229,648
Other derivative instruments, Trading derivatives | Foreign exchange swaps
Derivatives
Derivative notionals	7,807,130	7,943,054
Other derivative instruments, Trading derivatives | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	4,830,776	3,737,063
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Written
Derivatives
Derivative notionals	967,819	778,397
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	955,022	771,134
Other derivative instruments, Trading derivatives | Equity contracts
Derivatives
Derivative notionals	1,359,046	1,362,973
Other derivative instruments, Trading derivatives | Equity swaps
Derivatives
Derivative notionals	289,732	317,117
Other derivative instruments, Trading derivatives | Equity futures and forwards
Derivatives
Derivative notionals	70,303	72,592
Other derivative instruments, Trading derivatives | Equity contract options | Written
Derivatives
Derivative notionals	555,561	544,315
Other derivative instruments, Trading derivatives | Equity contract options | Purchased
Derivatives
Derivative notionals	443,450	428,949
Other derivative instruments, Trading derivatives | Commodity and other contracts
Derivatives
Derivative notionals	332,180	340,117
Other derivative instruments, Trading derivatives | Commodity and other swaps
Derivatives
Derivative notionals	76,194	82,009
Other derivative instruments, Trading derivatives | Commodity and other futures and forwards
Derivatives
Derivative notionals	151,006	161,811
Other derivative instruments, Trading derivatives | Commodity and other contracts | Written
Derivatives
Derivative notionals	53,308	49,555
Other derivative instruments, Trading derivatives | Commodity and other contracts | Purchased
Derivatives
Derivative notionals	51,672	46,742
Other derivative instruments, Trading derivatives | Credit derivatives
Derivatives
Derivative notionals	1,102,570	1,064,326
Other derivative instruments, Trading derivatives | Credit derivatives | Written
Derivatives
Derivative notionals	513,714	496,699
Other derivative instruments, Trading derivatives | Credit derivatives | Purchased
Derivatives
Derivative notionals	$ 588,856	$ 567,627