Investment Securities (Narrative) (Details) (USD $)	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Investment Securities Disclosure [Abstract]
Gross unrealized loss on debt securities held to maturity	$ 8,000,000		$ 5,000,000
Gross unrealized loss on debt securities held to maturity in a continuous loss position for less than 12 months - fair value	600,000,000		700,000,000
Available For Sale Transfer To Held To Maturity	2,900,000,000	3,400,000,000
Agency Residential Mbs Transfer To Held To Maturity	1,900,000,000
Agency Commercial Mbs Transfer To Held To Maturity	323,000,000
Net Pretax Unrealized Gain On Afs To Htm Transfer	143,000,000	40,000,000
State And Municipal Securities Transfer To Held To Maturity	$ 662,000,000