Fair Value of Financial Instruments (Details 5) (USD $) In Thousands, unless otherwise specified				9 Months Ended			9 Months Ended						9 Months Ended			9 Months Ended		9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Loans held-for-sale, fair value option	Sep. 30, 2013 Loans held-for-sale, fair value option Discounted cash flow Minimum Recurring basis	Sep. 30, 2013 Loans held-for-sale, fair value option Discounted cash flow Maximum Recurring basis	Sep. 30, 2013 RMBS	Sep. 30, 2013 RMBS Discounted cash flow	Sep. 30, 2013 RMBS Discounted cash flow Minimum	Sep. 30, 2013 RMBS Discounted cash flow Minimum Recurring basis	Sep. 30, 2013 RMBS Discounted cash flow Maximum	Sep. 30, 2013 RMBS Discounted cash flow Maximum Recurring basis	Sep. 30, 2013 CMBS and CMBS, fair value option	Sep. 30, 2013 CMBS and CMBS, fair value option Discounted cash flow Minimum Recurring basis	Sep. 30, 2013 CMBS and CMBS, fair value option Discounted cash flow Maximum Recurring basis	Sep. 30, 2013 Domestic Servicing Rights	Sep. 30, 2013 Domestic Servicing Rights Discounted cash flow Recurring basis	Sep. 30, 2013 VIE assets	Sep. 30, 2013 VIE assets Discounted cash flow Minimum Recurring basis	Sep. 30, 2013 VIE assets Discounted cash flow Maximum Recurring basis
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Carrying Value	$ 104,074,575	$ 4,324,373	$ 279,121			$ 316,261						$ 198,146			$ 158,023		$ 97,359,666
Yield (as a percent)				4.65%	5.61%								0.00%	767.00%		8.75%		0.00%	791.80%
Duration				5 years	10 years								0 years	10 years				0 years	23 years 6 months
Constant prepayment rate (as a percent)									(0.60%)		14.90%
Constant default rate (as a percent)									2.00%		13.30%
Loss severity (as a percent)									10.00%		83.00%
Delinquency Rate (as a percent)									5.00%		47.00%
Servicer Advances (as a percent)									8.00%		100.00%
Annual Coupon Deterioration (as a percent)									0.025%		0.18%
Putback Amount per Projected Total Collateral Loss (as a percent)									0.00%		9.00%
Discount rates (as a percent)																15.00%
Portfolio percentage							90.00%	40.00%		80.00%