Variable Interest Entities - Additional Information (Details) $ in Millions	3 Months Ended
	Jun. 30, 2017 USD ($) structured_note_vehicle	Dec. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Maximum exposure to loss	$ 3,685	$ 6,676
Number of structured note vehicles unwound | structured_note_vehicle	1
Gain from make-whole payment from third-party investment guarantor	$ 11
Structured note vehicles [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Maximum exposure to loss	3,013	$ 5,896
Trading Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment in structured note vehicle	$ 1,081