Acquisition and Discontinued Operations (Details Textual) (USD $)	3 Months Ended					3 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended
	Sep. 30, 2011	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Jan. 11, 2012 HSBC Bank Branches [Member] Branch	Sep. 30, 2011 Retained Earnings [Member]	Sep. 30, 2011 Retained Earnings [Member]	Dec. 31, 2010 Retained Earnings [Member]	Mar. 31, 2012 Segment, Discontinued Operations [Member]	Mar. 31, 2011 Segment, Discontinued Operations [Member]	Dec. 31, 2009 Segment, Discontinued Operations [Member] Trust	Mar. 31, 2012 Segment, Discontinued Operations [Member] Contractual Values [Member]	Mar. 31, 2012 Segment, Discontinued Operations [Member] Fair Value [Member]
Divestiture and Discontinued Operations (Textual) [Abstract]
Economic interest or risk of loss associated with Education loan securitization trusts									$ 205,000,000
Charges determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations, after tax									14,000,000	13,000,000
Loans held by the trust in nonaccrual status												16,000,000	16,000,000
Loans held by portfolio in nonaccrual status												1,000,000	1,000,000
Loans held by trusts with unpaid balances ninety days or more past due												41,000,000	40,000,000
Loans held by portfolio with unpaid balances ninety days or more past due												3,000,000	3,000,000
Number of outstanding securitization trusts											10
Cumulative effect adjustment with retained earnings due to re-measurement fair Value						45,000,000	45,000,000	45,000,000
Unearned Income		2,000,000	2,000,000	1,000,000
Overstate accrued income and other assets	30,000,000
Loans held by the trusts with unpaid principal balances due date									90 days or more
Loans held by the portfolio with unpaid principal balances due date									90 days or more
Divestiture and Discontinued Operations (Additional Textual) [Abstract]
Number of retail banking branches acquired in purchase and assumption agreement					37
Deposits assumed associated with branches acquired in purchase and assumption agreement					2,400,000,000
Loans purchased associated with branches acquired in purchase and assumption agreement					$ 400,000,000