Loans (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012 Y		Mar. 31, 2011		Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired nonaccrual commercial loans, minimum	$ 1,000,000
Troubled debt restructurings loans	303,300,000		285,100,000
Allowance for loan losses	346,016,000	[1],[2]	589,128,000	[1],[2]	384,351,000	664,799,000
Average balance of impaired loans	483,807,000		621,097,000
Interest income recognized	1,706,000		1,325,000
All commercial loans	1,000,000
Certain commercial loans that are graded 13 or worse	500,000
Forbearance agreements time period	generally 3 to 6 months
Consumer TDR, reduction of interest rate by increment, basis points	25
Modified interest rate, minimum consumer loan	1.00%
Modified interest rate time period, maximum for consumer loans	5
Credit card workout program, granted rate reduction, percentage, minimum	0.00%
Credit card workout program, maximum, term extension (in years)	5
Permanent Mortgage Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	32,572,000	[1],[2]	55,640,000	[1],[2]	26,194,000	65,009,000
Maximum maturities in years for TDRS	40
C&I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of commercial loan portfolio	8.00%
Loans Held-For-Sale [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans	126,300,000		62,600,000
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	42.00%
Consumer Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	34.00%
Allowance for loan losses	141,647,000	[1],[2]	179,394,000	[1],[2]	165,077,000	192,350,000
Maximum maturities in years for TDRS	20
Bank-Related And TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan	4.00%
Bank-related and trust preferred loans total	600,000,000
Modified Loans Classified As A TDR [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 49,900,000		$ 42,000,000
Allowance For TDRs To Recorded Investment Of TDRs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ratio of the allowance for loan losses to loans	16.00%		15.00%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payment reductions, time period	1
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payment reductions, time period	6

[1] Balances as of March 31, 2012 and 2011 include $20.1 million and $36.5 million of reserves, respectively, and $467.0 million and $672.4 million of balances in restricted consumer real estate loans and secured borrowings, respectively.

[2] Balances as of March 31, 2012 and 2011 include $5.4 million and $3.3 million of reserves, respectively, and $38.0 million and $49.9 million of balances in restricted permanent mortgage loans and secured borrowings, respectively.