Investment Securities (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2014
Investment Securities Disclosure [Abstract]
Gain on derivatives used to hedge purchase of investment securities	$ 63,000,000
Gross unrealized loss on debt securities held to maturity	22,000,000	98,000,000
Gross unrealized loss on debt securities held to maturity in a continuous loss position for less than 12 months - fair value	134,000,000	3,600,000,000
Available For Sale Transfer To Held To Maturity			1,400,000,000
Net Pretax Unrealized Gain On Afs To Htm Transfer			44,000,000
State And Municipal Securities Transfer To Held To Maturity			1,000,000,000
Gross unrealized loss on debt securities held to maturity in a continuous loss position greater than 12 months - fair value	1,600,000,000	48,000,000
Non Agency Commercial Mbs Transfer To Held To Maturity			200,000,000
Weighted Average Maturity	4 years 4 months	4 years 11 months
Agency Residential And Commercial Mbs Transfer To Held To Maturity			$ 200,000,000