Variable Interest Entities and Securitization Activities (Proceeds from retained interests in securitization transactions) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
OTC \| Equity Derivatives
Transfer of Financial Assets Accounted for as Sales
Carrying value of assets derecognized at the time of sale and gross cash proceeds	$ 14,817		$ 14,817		$ 11,209
Fair value of assets sold	14,710		14,710		11,301
Fair value of derivative assets recognized in the consolidated balance sheets	33		33		128
Fair value of derivative liabilities recognized in the consolidated balance sheets	140		140		$ 36
Special Purpose Entities
Transfer of Financial Assets Accounted for as Sales
Proceeds from new securitization transactions	4,750	$ 4,163	10,747	$ 6,876
Proceeds from retained interests in securitization transactions	529	502	959	1,133
CLO SPEs \| Corporate Loans
Transfer of Financial Assets Accounted for as Sales
Proceeds from sale of loans	$ 239	$ 0	$ 418	$ 31

Cash Flows between a transferor and a transferee attributable to newly transferred assets related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

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-Publisher FASB
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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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