Securities - OTTI Significant Assumptions (Details) - Non-agency residential	Sep. 30, 2016
Weighted Average
Significant Assumptions:
Annual prepayment speed	14.20%
Loss severity	20.10%
Life default rate	20.60%
Weighted Average \| Prime
Significant Assumptions:
Loss severity	17.30%
Life default rate	14.20%
Weighted Average \| Alt-A Loan
Significant Assumptions:
Loss severity	18.80%
Life default rate	21.80%
Weighted Average \| Subprime
Significant Assumptions:
Loss severity	30.60%
Life default rate	21.50%
10th Percentile
Significant Assumptions:
Annual prepayment speed	4.90%
Loss severity	8.70%
Life default rate	0.70%
90th Percentile
Significant Assumptions:
Annual prepayment speed	28.00%
Loss severity	36.80%
Life default rate	78.20%