Fair Values - Net Revenues from Borrowings under the Fair Value Option (Details) - Borrowings - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value Option Quantitative Disclosures
Earnings impact	$ (888)	$ 390	$ (6,168)	$ 1,100
Trading revenues
Fair Value Option Quantitative Disclosures
Earnings impact	(795)	449	(5,888)	1,334
Interest expense
Fair Value Option Quantitative Disclosures
Earnings impact	$ 93	$ 59	$ 280	$ 234