Collateralized Transactions (Gross Secured Financing Balances) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Gross Secured Financing Balances
Securities sold under agreements to repurchase	$ 156,827	$ 171,210
Securities loaned	27,068	23,014
Total included in the offsetting disclosure	183,895	194,224
Trading liabilities - Obligation to return securities received as collateral	18,746	22,555
Total	202,641	216,779
U.S. Government and Agency Securities
Gross Secured Financing Balances
Securities sold under agreements to repurchase	37,361	43,346
Securities loaned	6	81
State and Municipal Securities
Gross Secured Financing Balances
Securities sold under agreements to repurchase	1,643	2,451
Other Sovereign Government Obligations
Gross Secured Financing Balances
Securities sold under agreements to repurchase	78,844	87,141
Securities loaned	14,077	9,489
ABS
Gross Secured Financing Balances
Securities sold under agreements to repurchase	2,204	1,130
Corporate and Other Debt
Gross Secured Financing Balances
Securities sold under agreements to repurchase	10,063	7,737
Securities loaned	28	14
Corporate Equities
Gross Secured Financing Balances
Securities sold under agreements to repurchase	25,893	28,497
Securities loaned	12,770	13,174
Trading liabilities - Obligation to return securities received as collateral	18,746	22,555
Other
Gross Secured Financing Balances
Securities sold under agreements to repurchase	819	908
Securities loaned	187	256
Trading liabilities - Obligation to return securities received as collateral	0	0
Overnight and Open
Gross Secured Financing Balances
Securities sold under agreements to repurchase	39,192	41,332
Securities loaned	16,869	12,130
Total included in the offsetting disclosure	56,061	53,462
Trading liabilities - Obligation to return securities received as collateral	18,136	22,555
Total	74,197	76,017
Less than 30 days
Gross Secured Financing Balances
Securities sold under agreements to repurchase	49,822	66,593
Securities loaned	603	873
Total included in the offsetting disclosure	50,425	67,466
Trading liabilities - Obligation to return securities received as collateral	0	0
Total	50,425	67,466
30-90 days
Gross Secured Financing Balances
Securities sold under agreements to repurchase	27,926	28,682
Securities loaned	2,045	1,577
Total included in the offsetting disclosure	29,971	30,259
Trading liabilities - Obligation to return securities received as collateral	610	0
Total	30,581	30,259
Over 90 days
Gross Secured Financing Balances
Securities sold under agreements to repurchase	39,887	34,603
Securities loaned	7,551	8,434
Total included in the offsetting disclosure	47,438	43,037
Trading liabilities - Obligation to return securities received as collateral	0	0
Total	$ 47,438	$ 43,037

The aggregate amount of liabilities as of the balance sheet date for obligations incurred in connection with the entity's investments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15)
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 55
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 7
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=64858031&loc=SL34722452-111729

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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