DERIVATIVES - Credit Derivatives (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) counterparty agency	Dec. 31, 2019 USD ($)
Credit Derivative
Percentage of receivables from counterparties with collateral agreements	97.00%	98.00%
Number of top counterparties which are banks, financial institutions, and other dealers | counterparty	15
Fair value, Receivable	$ 9,789	$ 10,409
Fair Value, Payable	10,129	10,738
Notionals, Protection purchased	612,770	703,926
Notionals, Protection sold	543,607	603,387
Fair value of derivative in liability position	25,000	30,000
Fair value of collateral already posted	$ 22,000	28,000
Number of rating agencies | agency	3
Additional collateral to be posted	$ 800
Collateral to be segregated	200
Aggregate cash obligations and collateral requirements	1,000
Purchased
Credit Derivative
Fair value, Receivable	3,514	3,415
Fair Value, Payable	7,037	7,793
Sold
Credit Derivative
Fair value, Receivable	6,275	6,994
Fair Value, Payable	3,092	2,945
Within 1 year
Credit Derivative
Fair value, Receivable	914	1,806
Fair Value, Payable	1,355	2,181
Notionals, Protection purchased	134,080	231,135
Notionals, Protection sold	125,464	176,188
From 1 to 5 years
Credit Derivative
Fair value, Receivable	6,022	7,275
Fair Value, Payable	5,991	7,265
Notionals, Protection purchased	421,682	414,237
Notionals, Protection sold	374,376	379,915
After 5 years
Credit Derivative
Fair value, Receivable	2,853	1,328
Fair Value, Payable	2,783	1,292
Notionals, Protection purchased	57,008	58,554
Notionals, Protection sold	43,767	47,284
Investment Grade
Credit Derivative
Fair value, Receivable	4,136	4,579
Fair Value, Payable	4,037	4,578
Notionals, Protection purchased	478,643	560,806
Notionals, Protection sold	418,147	470,778
Non-Investment Grade
Credit Derivative
Fair value, Receivable	5,653	5,830
Fair Value, Payable	6,092	6,160
Notionals, Protection purchased	134,127	143,120
Notionals, Protection sold	125,460	132,609
Credit default swaps and options
Credit Derivative
Fair value, Receivable	9,254	9,759
Fair Value, Payable	9,254	9,791
Notionals, Protection purchased	599,633	685,643
Notionals, Protection sold	538,426	593,850
Total return swaps and other
Credit Derivative
Fair value, Receivable	535	650
Fair Value, Payable	875	947
Notionals, Protection purchased	13,137	18,283
Notionals, Protection sold	5,181	9,537
Banks
Credit Derivative
Fair value, Receivable	2,902	4,017
Fair Value, Payable	3,187	4,102
Notionals, Protection purchased	117,685	172,461
Notionals, Protection sold	120,739	169,546
Broker-dealers
Credit Derivative
Fair value, Receivable	1,770	1,724
Fair Value, Payable	1,215	1,528
Notionals, Protection purchased	46,928	54,843
Notionals, Protection sold	44,692	53,846
Non-financial
Credit Derivative
Fair value, Receivable	109	92
Fair Value, Payable	90	76
Notionals, Protection purchased	5,740	2,601
Notionals, Protection sold	2,217	1,968
Insurance and other financial institutions
Credit Derivative
Fair value, Receivable	5,008	4,576
Fair Value, Payable	5,637	5,032
Notionals, Protection purchased	442,417	474,021
Notionals, Protection sold	375,959	378,027
Interest rate swaps
Credit Derivative
Amount derecognized	2,000	5,800
Cash proceeds received for assets derecognized	2,000	5,800
Fair value of derecognized assets	2,200	5,900
Fair value gross derivative assets	135	117
Trading derivatives, liability	$ 7	$ 43