Investments - Narrative (Details) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($) positions	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Percentage of Fixed Income Investment portfolio invested in below investment grade or not rated	2.10%		2.00%
Percentage of Gross Unrealized losses in Fixed income securities portfolio related to securities below investment grade or not rated	18.30%		14.70%
Pledged Assets Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	$ 19,000,000		$ 18,300,000
Available for sale securities, Gross unrealized losses	$ 239,691		369,975
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions \| positions	1,934
Available-for-sale Securities, Qualitative Disclosure, Number of Positions \| positions	8,763
Change in adjustments related to future policy benefit reserves, net of tax	$ 17,035	$ 60,356
Fixed maturities, at fair value	32,647,573		32,257,589
Amortized cost of fixed maturities	31,444,747		31,517,654
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	4,877	28,539
Unrealized gains (losses) on investments
Schedule of Available-for-sale Securities [Line Items]
Change in adjustments related to future policy benefit reserves, net of tax	17,000
Excluding Life Funds Withheld Assets
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Gross unrealized losses	239,691		369,975
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	19,580	$ 10,576
Fixed maturities, at fair value	29,684,216		29,104,486
Amortized cost of fixed maturities	29,016,396		28,839,622
Excluding Life Funds Withheld Assets \| Corporate
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	9,800
Excluding Life Funds Withheld Assets \| Equities
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	7,000
Excluding Life Funds Withheld Assets \| Collateralized debt obligations
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	600
Fixed maturities, at fair value	21,729		32,410
Amortized cost of fixed maturities	25,845		$ 41,679
Excluding Life Funds Withheld Assets \| Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	300
Excluding Life Funds Withheld Assets \| Foreign Exchange [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	$ 1,900

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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