Securities Financing Activities - Schedule of securities purchased under resale agreements, netting & securities borrowed (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Securities purchased under resale agreements:
Securities purchased under resale agreements with an appropriate legal opinion, Gross asset balance	$ 341,989,000,000	$ 354,814,000,000
Amounts netted on the Consolidated Balance Sheets	(142,719,000,000)	(115,408,000,000)
Securities purchased under resale agreements with an appropriate legal opinion, Net asset balance	199,270,000,000	239,406,000,000
Securities purchased under resale agreements where an appropriate legal opinion has not been either sought or obtained	15,751,000,000	8,279,000,000
Total securities purchased under resale agreements, gross asset balance	357,740,000,000	363,093,000,000
Total securities purchased under resale agreements, net asset balance	215,021,000,000	247,685,000,000
Securities borrowed	110,435,000,000	111,465,000,000
Securities borrowed where an appropriate legal opinion has not been either sought or obtained	28,000,000,000	26,900,000,000
Securities Financing Transaction, Fair Value
Securities purchased under resale agreements:
Total securities purchased under resale agreements, net asset balance	28,600,000,000	25,100,000,000
Securities borrowed, fair value	$ 992,000,000	$ 3,700,000,000