Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Principles - Collateral (Details)

v2.4.1.9
Summary of Significant Accounting Principles - Collateral (Details) (USD $)
In Billions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Accounting Policies [Abstract]    
Securities held as collateral, fair value $ 519.2us-gaap_SecuritiesHeldAsCollateralAtFairValue $ 575.3us-gaap_SecuritiesHeldAsCollateralAtFairValue
Securities received as collateral, amount re-pledged and sold $ 424.5us-gaap_SecuritiesReceivedAsCollateralAmountRepledgedAndSold $ 430.4us-gaap_SecuritiesReceivedAsCollateralAmountRepledgedAndSold