Repurchase Arrangements And Similar Borrowings, Including Related Hedging Activity (Narrative) (Details)	9 Months Ended
	Sep. 30, 2011
Repurchase Arrangements And Similar Borrowings, Including Related Hedging Activity [Line Items]
Swap agreements average expiration period	15
Percentage of haircuts on pledged agency securities	4.60
Maximum [Member]
Repurchase Arrangements And Similar Borrowings, Including Related Hedging Activity [Line Items]
Maturity period of repurchase arrangements (days)	90
Minimum [Member]
Repurchase Arrangements And Similar Borrowings, Including Related Hedging Activity [Line Items]
Maturity period of repurchase arrangements (days)	30