Variable Interest Entities - Credit Card Securitizations (Details) - Firm-sponsored credit card trusts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Minimum undivided interest in credit card trusts	22.00%	22.00%
Undivided interests in Firm-sponsored credit card securitization trusts	$ 13,600	$ 10,900
Senior securities
Variable Interest Entity [Line Items]
Undivided interests in Firm-sponsored credit card securitization trusts	0	40
Subordinated securities
Variable Interest Entity [Line Items]
Undivided interests in Firm-sponsored credit card securitization trusts	$ 5,300	$ 5,300
Minimum
Variable Interest Entity [Line Items]
Minimum undivided interest in credit card trusts	4.00%