DERIVATIVES - Credit Derivatives (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) agency	Dec. 31, 2020 USD ($)
Credit Risk Derivatives
Fair values, receivable	$ 10,242	$ 9,789
Fair values, payable	10,649	10,129
Notionals, protection purchased	705,590	612,770
Notionals, protection sold	634,497	543,607
Fair value of derivative in liability position	20,000	25,000
Fair value of collateral already posted	$ 18,000	22,000
Number of rating agencies | agency	3
Additional collateral to be posted	$ 1,500
Collateral to be segregated	100
Aggregate cash obligations and collateral requirements	1,600
Purchased
Credit Risk Derivatives
Fair values, receivable	3,729	3,514
Fair values, payable	7,244	7,037
Sold
Credit Risk Derivatives
Fair values, receivable	6,513	6,275
Fair values, payable	3,405	3,092
Within 1 year
Credit Risk Derivatives
Fair values, receivable	783	914
Fair values, payable	1,274	1,355
Notionals, protection purchased	131,085	134,080
Notionals, protection sold	121,324	125,464
From 1 to 5 years
Credit Risk Derivatives
Fair values, receivable	6,188	6,022
Fair values, payable	6,192	5,991
Notionals, protection purchased	460,850	421,682
Notionals, protection sold	419,029	374,376
After 5 years
Credit Risk Derivatives
Fair values, receivable	3,271	2,853
Fair values, payable	3,183	2,783
Notionals, protection purchased	113,655	57,008
Notionals, protection sold	94,144	43,767
Investment grade
Credit Risk Derivatives
Fair values, receivable	4,179	4,136
Fair values, payable	4,053	4,037
Notionals, protection purchased	541,747	478,643
Notionals, protection sold	478,178	418,147
Non-investment grade
Credit Risk Derivatives
Fair values, receivable	6,063	5,653
Fair values, payable	6,596	6,092
Notionals, protection purchased	163,843	134,127
Notionals, protection sold	156,319	125,460
Credit default swaps and options
Credit Risk Derivatives
Fair values, receivable	9,609	9,254
Fair values, payable	9,927	9,254
Notionals, protection purchased	689,107	599,633
Notionals, protection sold	626,484	538,426
Total return swaps and other
Credit Risk Derivatives
Fair values, receivable	633	535
Fair values, payable	722	875
Notionals, protection purchased	16,483	13,137
Notionals, protection sold	8,013	5,181
Banks
Credit Risk Derivatives
Fair values, receivable	2,384	2,902
Fair values, payable	3,060	3,187
Notionals, protection purchased	112,636	117,685
Notionals, protection sold	108,122	120,739
Broker-dealers
Credit Risk Derivatives
Fair values, receivable	1,984	1,770
Fair values, payable	1,229	1,215
Notionals, protection purchased	50,752	46,928
Notionals, protection sold	44,525	44,692
Non-financial
Credit Risk Derivatives
Fair values, receivable	125	109
Fair values, payable	75	90
Notionals, protection purchased	6,056	5,740
Notionals, protection sold	2,635	2,217
Insurance and other financial institutions
Credit Risk Derivatives
Fair values, receivable	5,749	5,008
Fair values, payable	6,285	5,637
Notionals, protection purchased	536,146	442,417
Notionals, protection sold	479,215	375,959
Interest rate swaps
Credit Risk Derivatives
Cash proceeds received for assets derecognized	1,600	2,000
Fair value of derecognized assets	1,600	2,200
Fair value gross derivative assets	53	135
Trading derivatives, liability	$ 18	$ 7