Summary of Significant Accounting Policies Allowance For Credit Losses (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Loan Balances Allocated Reserves	$ 1,000,000
Percentage Threshold Of Companies Current Loan To Value Ratio Of Original Appraisals Used	80.00%
Financing Receivable, Individually Evaluated for Impairment		525,600,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		164,200,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		106,000,000
Financing Receivable, Collectively Evaluated for Impairment		11,300,000,000
Percentage Of Impaired Loans With Primary Collateral As Real Estate	78.00%		52.00%
Impaired Loans Balances, Real Estate as Collateral	1,000,000
Period For Which Change In Loans Are Evaluated Individually For Impairment Quarterly	12 months
Period For Which Changes In Loans Are Evaluated Individually For Impairment	90 days
Financing Receivable, Allowance for Credit Losses	258,177,000	271,200,000	275,498,000	257,553,000	180,137,000
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Number Of Days Closed End Consumer Loans Are Charged Off When They Become Past Due	120 days
Number Of Days Open End Consumer Loans Are Charged Off When They Become Past Due	180 days
Change in Accounting Method Accounted for as Change in Estimate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment		335,600,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		182,200,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		88,000,000
Financing Receivable, Collectively Evaluated for Impairment		$ 11,500,000,000