Financial and Other Derivative Instruments (Details Textuals) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Letters of credit that could be used to offset net derivative liabilities	$ 21	$ 19
Cash Collateral Posted Net of Cash Collateral Received	40	12
Cash Collateral Paid or Received for Derivative Assets	4	26
Cash Collateral Paid or Received for Derivative Liabilities	42	17
Cash Collateral Received	2	13
Cash Collateral Paid	4	34
Derivative, Net Liability Position, Aggregate Fair Value	894
Collateral Already Posted, Aggregate Fair Value	13
Derivative, Net Asset Position, Aggregate Fair Value	744
Remaining amount of offsets to derivative net liability positions for hard and soft trigger provisions	137
Additional Collateral, Aggregate Fair Value	$ 327