Investments - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended								3 Months Ended		9 Months Ended					3 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended				3 Months Ended
	Sep. 30, 2014 positions	Sep. 30, 2013	Sep. 30, 2014 positions	Sep. 30, 2013	May 01, 2014	Dec. 31, 2013	Dec. 31, 2013 Corporate	Sep. 30, 2014 Medium term notes	Dec. 31, 2013 Medium term notes	Sep. 30, 2014 Structured Credit Securities [Member]	Sep. 30, 2014 RMBS - Non-Agency	Sep. 30, 2013 RMBS - Non-Agency	Sep. 30, 2014 RMBS - Non-Agency	Sep. 30, 2013 RMBS - Non-Agency	Dec. 31, 2013 RMBS - Non-Agency	Sep. 30, 2014 Core Cdo Holdings	Sep. 30, 2014 XL Re Life (SAC) Ltd [Member]	Sep. 30, 2014 Unrealized gains (losses) on investments	Jun. 30, 2014 Unrealized gains (losses) on investments	Sep. 30, 2013 Unrealized gains (losses) on investments	Sep. 30, 2014 Unrealized gains (losses) on investments	Sep. 30, 2013 Unrealized gains (losses) on investments	Sep. 30, 2014 Excluding Life Funds Withheld Assets	Sep. 30, 2013 Excluding Life Funds Withheld Assets	Sep. 30, 2014 Excluding Life Funds Withheld Assets	Sep. 30, 2013 Excluding Life Funds Withheld Assets	Sep. 30, 2014 Excluding Life Funds Withheld Assets Corporate	Sep. 30, 2014 Excluding Life Funds Withheld Assets RMBS - Non-Agency	Sep. 30, 2014 Excluding Life Funds Withheld Assets Equities
Schedule of Available-for-sale Securities [Line Items]
Held To Maturity Securities Transferred Security Carrying Value																	$ 2,800,000,000
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax	0		0		424,900,000	274,150,000	113,179,000								4,985,000
Fixed maturites held to maturity, gross unrealized losses	0		0		0	1,610,000	968,000								0
Change in adjustments related to future policy benefit reserves, net of tax																		(51,286,000)	440,500,000	37,503,000	423,179,000	70,305,000
Fixed maturities, at fair value	29,806,144,000		29,806,144,000			27,500,136,000	11,125,830,000	152,400,000	154,600,000						398,768,000								24,543,059,000		24,543,059,000		9,427,025,000	435,654,000
Amortized cost of fixed maturities	28,418,355,000		28,418,355,000			27,111,874,000	10,802,332,000	141,100,000	147,700,000						396,798,000								23,861,565,000		23,861,565,000		9,117,201,000	412,443,000
Percentage of Fixed Income Investment portfolio invested in below investment grade or not rated	3.20%		3.20%			2.60%
Percentage of Gross Unrealized losses in Fixed income securities portfolio related to securities below investment grade or not rated	21.30%		21.30%			12.40%
Available for sale securities, Gross unrealized losses	197,710,000		197,710,000			437,036,000																	197,710,000		197,710,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	1,930		1,930
Available-for-sale Securities, Qualitative Disclosure, Number of Positions	7,660		7,660
Marketable Securities										5,100,000
Marketable Securities Unrealized Loss Other Than Temporary Impairments Amount										10,100,000	100,000		100,000			9,900,000
Impaired Investment Cumulative Fair Value Decline Percentage Amortized Cost										50.00%
Pledged Assets Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	15,700,000,000		15,700,000,000			15,500,000,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities											800,000												1,144,000	3,187,000	29,487,000	10,214,000			200,000
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	$ 1,840,000	$ 17,341,000	$ 10,042,000	$ 78,960,000							$ 900,000	$ 3,100,000	$ 6,100,000	$ 63,300,000