Variable Interest Entities - Additional Information (Details) - Variable Interest Entity, Not Primary Beneficiary, Structured Note Vehicles [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Sep. 30, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Maximum exposure to loss			$ 1,515
Loss on structured note settlement	$ 39
Carrying value of structured note vehicle			$ 1,524
Trading Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Carrying value of structured note vehicle	$ 1,293	$ 501