Fair Value Accounting - Significant Unobservable Inputs (Details) - Available-for-sale Securities [Member] - Mortgage securities [Member] - Present Value Analysis [Member] - Fair Value, Inputs, Level 3 [Member]	12 Months Ended
	Dec. 31, 2015
Fair Value Inputs, Quantitative Information [Line Items]
Fair value inputs, weighted average life, in years	2 years
Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Fair value inputs, prepayment rates	8.00%
Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Fair value inputs, prepayment rates	11.50%