Financial Derivatives (Total Gross Derivatives) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative Asset, Fair Value	$ 4,851	$ 5,234
Derivative Liability, Fair Value	3,827	4,027
Derivative Notional Amount	371,549	340,317
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Asset, Fair Value	1,172	1,261
Derivative Liability, Fair Value	225	186
Derivative Notional Amount	53,342	49,061
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Asset, Fair Value	3,679	3,973
Derivative Liability, Fair Value	3,602	3,841
Derivative Notional Amount	$ 318,207	$ 291,256