Loans - Wholesale RealEstate Loans, Credit Rating (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Wholesale Real Estate Loans
Retained loans	$ 692,944	$ 685,498	$ 687,049
Wholesale
Wholesale Real Estate Loans
Retained loans	255,799	222,510
Wholesale | Commercial and industrial [Member]
Wholesale Real Estate Loans
Retained loans	82,224	66,576
Wholesale | Real estate [Member]
Wholesale Real Estate Loans
Retained loans	53,596	53,635
Criticized exposure	5,568	8,706
% of criticized exposure to total real estate retained loans	10.39%	16.23%
Criticized nonaccrual	1,179	2,937
% of criticized nonaccrual to total real estate retained loans	2.20%	5.48%
Wholesale | Multi-family [Member]
Wholesale Real Estate Loans
Retained loans	32,042	30,604
Criticized exposure	2,926	3,798
% of criticized exposure to total real estate retained loans	9.13%	12.41%
Criticized nonaccrual	598	1,016
% of criticized nonaccrual to total real estate retained loans	1.87%	3.32%
Wholesale | Commercial lessors [Member]
Wholesale Real Estate Loans
Retained loans	14,363	15,796
Criticized exposure	1,849	3,593
% of criticized exposure to total real estate retained loans	12.87%	22.75%
Criticized nonaccrual	333	1,549
% of criticized nonaccrual to total real estate retained loans	2.32%	9.81%
Wholesale | Commercial construction and development [Member]
Wholesale Real Estate Loans
Retained loans	3,073	3,395
Criticized exposure	365	619
% of criticized exposure to total real estate retained loans	11.88%	18.23%
Criticized nonaccrual	134	174
% of criticized nonaccrual to total real estate retained loans	4.36%	5.13%
Wholesale | Wholesale Realestate Others [Member]
Wholesale Real Estate Loans
Retained loans	4,118	3,840
Criticized exposure	428	696
% of criticized exposure to total real estate retained loans	10.39%	18.13%
Criticized nonaccrual	114	198
% of criticized nonaccrual to total real estate retained loans	2.77%	5.16%
Wholesale | Financial institutions [Member]
Wholesale Real Estate Loans
Retained loans	35,505	31,458
Wholesale | Government agencies [Member]
Wholesale Real Estate Loans
Retained loans	7,551	7,278
Wholesale | Other [Member]
Wholesale Real Estate Loans
Retained loans	$ 76,923	$ 63,563