Investments (Proceeds from Sales of Available-For-Sale Securities and the Gross Realized Gains and Gross Realized Losses) (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
		Mar. 01, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016		Jun. 30, 2015
Investment [Line Items]
Proceeds from sales			$ 606,531	$ 804,476	$ 2,874,248		$ 1,356,989
Gross realized gains (a)			14,667	13,912	190,984	[1]	26,255
Gross realized losses (b)			$ 5,110	$ 5,844	31,571	[2]	$ 11,443
Employee Benefits Segment | Disposal Group, Not Discontinued Operations
Investment [Line Items]
Gross realized gains (a)	[1]				150,701
Gross realized losses (b)	[2]				$ 16,427
Investments transferred	[3]	$ 146,727

[1] Six months ended June 30, 2016 gross realized gains includes $150,701 related to the sale of Assurant Employee Benefits as described in Note 5.

[2] Six months ended June 30, 2016 gross realized losses includes $16,427 related to the sale of Assurant Employee Benefits as described in Note 5.

[3] Reinsurance of existing claims liabilities requires retroactive accounting necessitating losses to be recognized immediately. However, upon transfer of the associated assets supporting the liabilities, the Company recognized realized gains which more than offset the retroactive losses. The Company was required to classify the realized gains as part of net realized gains on investments, within the Consolidated Statements of Operations.