Fair Value (Details) - Significant Unobservable Inputs Used In The Valuation of CDOs - CDOs	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Probability of prepayment	0.00%	1.80%
Probability of default	16.70%	19.10%
Loss given default	93.30%	93.80%
Probability of deferral cure	7.60%	15.20%
Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Probability of prepayment	10.90%	15.10%
Probability of default	46.80%	32.60%
Loss given default	98.90%	97.10%
Probability of deferral cure	100.00%	63.10%