Segment and Geographic Information (Net Revenues by Region) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Net revenues	$ 11,077	$ 9,745
Americas
Segment Reporting Information
Net revenues	8,018	7,088
EMEA
Segment Reporting Information
Net revenues	1,708	1,489
Asia
Segment Reporting Information
Net revenues	$ 1,351	$ 1,168

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income after deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

No definition available.

Name:	us-gaap_RevenuesNetOfInterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration