Variable Interest Entities - Securitization Activity (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Variable Interest Entity (VIE) or Potential VIE, Information Unavailability [Member] | Residential Mortgage [Member]
Securitization activity [Abstract]
Principal securitized	$ 0	$ 0	$ 35
All cash flows during the period:
Proceeds from new securitizations	0	0	36
Servicing fees collected	662	755	968
Purchases of previously transferred financial assets (or the underlying collateral)	222	772	321
Cash flows received on the interests that continue to be held by the Firm	185	235	319
Variable Interest Entity (VIE) or Potential VIE, Information Unavailability [Member] | Commercial Mortgage Backed Securities [Member]
Securitization activity [Abstract]
Principal securitized	5,421	5,961	2,237
All cash flows during the period:
Proceeds from new securitizations	5,705	6,142	2,369
Servicing fees collected	4	4	4
Purchases of previously transferred financial assets (or the underlying collateral)	0	0	0
Cash flows received on the interests that continue to be held by the Firm	163	178	143
Variable Interest Entity (VIE) or Potential VIE, Information Unavailability [Member] | Commercial mortgage [Member]
All cash flows during the period:
Weighted-average life (in years)	8 years 9 months 3 days	1 year 8 months 12 days	7 years 1 month 6 days
Discount rate	3.60%	3.50%	7.70%
Fair Value, Inputs, Level 2 [Member] | Residential and commercial mortgage securitizations [Member]
All cash flows during the period:
Proceeds from new securitizations	5,700	4,000	2,200
Fair Value, Inputs, Level 3 [Member] | Residential and commercial mortgage securitizations [Member]
All cash flows during the period:
Proceeds from new securitizations		$ 2,100	$ 172