Financial Derivatives (Risk Participation Agreements Sold) (Details) - Risk Participation Agreements Sold [Member] - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Credit Derivatives [Line Items]
Notional Amount	$ 2,669	$ 2,796
Fair Value	$ (5)	$ (4)
Average term of credit risk derivatives	5 years	5 years 5 months