Investments Realized Gains (Losses) on Investments (Details)	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Gain (Loss) on Investments [Line Items]
Sale of bonds, number of securities sold at a loss	0	0
Sale of bonds, number of held-to-maturity bonds sold	0	0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration