SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Repurchase Agreements (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	$ 283,795	$ 253,514
Deposits received for securities loaned	17,145	11,678
Total	300,940	265,192
U.S. Treasury and federal agency securities
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	103,718	86,785
Deposits received for securities loaned	91	41
Total	103,809	86,826
State and municipal securities
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	2,170	2,605
Deposits received for securities loaned	4	0
Total	2,174	2,605
Foreign government
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	108,497	99,131
Deposits received for securities loaned	264	179
Total	108,761	99,310
Corporate bonds
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	21,255	21,719
Deposits received for securities loaned	474	749
Total	21,729	22,468
Equity securities
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	14,092	12,920
Deposits received for securities loaned	16,011	10,664
Total	30,103	23,584
Mortgage-backed securities
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	23,813	19,421
Deposits received for securities loaned	0	0
Total	23,813	19,421
Asset-backed securities
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	5,808	6,207
Deposits received for securities loaned	0	0
Total	5,808	6,207
Other
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	4,442	4,726
Deposits received for securities loaned	301	45
Total	4,743	4,771
Open and overnight
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	143,154	108,405
Deposits received for securities loaned	11,123	6,296
Total	154,277	114,701
Up to 30 days
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	67,183	70,850
Deposits received for securities loaned	481	774
Total	67,664	71,624
31–90 days
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	31,487	29,898
Deposits received for securities loaned	2,201	2,626
Total	33,688	32,524
Greater than 90 days
Assets Sold under Agreements to Repurchase
Securities sold under agreements to repurchase	41,971	44,361
Deposits received for securities loaned	3,340	1,982
Total	$ 45,311	$ 46,343