Investments in Affiliates - Investment Fund Consolidation (Details) (USD $)	12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2011	May 31, 2012
Investment Fund Consolidation [Line Items]
Fixed maturities, AFS, at fair value	$ 27,500,136,000		$ 29,359,034,000
Amortized cost of fixed maturities, available for sale	27,111,874,000		27,728,771,000
Asset derivative fair value	26,145,000		135,963,000
Cash and cash equivalents	1,800,832,000		2,521,814,000	2,618,378,000	3,825,125,000
Other liabilities	950,845,000		912,748,000
Non-controlling interest in equity of consolidated subsidiaries	1,351,665,000		1,402,015,000
Cost of operating affiliate interests acquired	30,000,000
Five Oaks Investment Corp [Member]
Investment Fund Consolidation [Line Items]
Investment amount						25,000,000
Percentage ownership						94.00%
Sale of Stock, Percentage of Ownership after Transaction		43.80%
Deconsolidation, Gain (Loss), Amount		1,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			3,125,000
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 15.75
Cost of operating affiliate interests acquired			49,200,000
Ownership percentage remaining			21.90%
Five Oaks Investment Corp [Member] | IPO [Member]
Investment Fund Consolidation [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		4,000,000
Sale of Stock, Consideration Received Per Transaction		61,000,000
Five Oaks Investment Corp [Member] | Private Placement [Member]
Investment Fund Consolidation [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		1,670,000
Sale of Stock, Consideration Received Per Transaction		$ 25,000,000
Five Oaks Investment Corp [Member] | Received in Distribution [Member]
Investment Fund Consolidation [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		8,175