Derivatives and Hedging Activities (Option Pay/Rec) (Details 4) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	$ 1,924
Premiums Receivable For Derivatives Option Contracts	478
2015 [Member]
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	393
Premiums Receivable For Derivatives Option Contracts	70
2016 [Member]
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	333
Premiums Receivable For Derivatives Option Contracts	69
2017 [Member]
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	271
Premiums Receivable For Derivatives Option Contracts	70
2018 [Member]
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	208
Premiums Receivable For Derivatives Option Contracts	80
2019 [Member]
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	226
Premiums Receivable For Derivatives Option Contracts	71
2020-2027 [Member]
Summary of Option Premiums Payable and Receivable [Line Items]
Premiums Payable For Derivatives Option Contracts	493
Premiums Receivable For Derivatives Option Contracts	$ 118