SOI Unrealized losses fixed maturities AFS (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 position	Dec. 31, 2013 position
Fixed maturities
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	$ 1,561,784	$ 5,763,951
Less than twelve months, Unrealized loss and OTTI	18,696	207,170
Twelve months or longer, Estimated fair value	1,161,371	885,337
Twelve months or longer, Unrealized loss and OTTI	82,747	101,052
Total Estimated fair value	2,723,155	6,649,288
Total Unrealized losses and OTTI	101,443	308,222
Additional disclosure
Total number of securities in an unrealized loss position, Less than twelve months	134	458
Total number of securities in an unrealized loss position, twelve months or longer	153	109
Total number of securities in an unrealized loss position	287	567
Increase (decrease) in total unrealized losses and other-than-temporary impairment losses	206,779
Increase in total unrealized losses and other-than-temporary impairment losses (as a percent)	67.00%
Increase (decrease) in less than twelve months unrealized losses and other-than-temporary impairment losses	188,474
Increase (decrease) in greater than twelve months unrealized losses and other-than-temporary impairment losses	(18,305)
U.S. government direct obligations and U.S. agencies
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	566,335	2,399,373
Less than twelve months, Unrealized loss and OTTI	503	23,156
Twelve months or longer, Estimated fair value	74,322	5,192
Twelve months or longer, Unrealized loss and OTTI	991	217
Total Estimated fair value	640,657	2,404,565
Total Unrealized losses and OTTI	1,494	23,373
Obligations of U.S. states and their subdivisions
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	18,280	214,979
Less than twelve months, Unrealized loss and OTTI	218	16,713
Twelve months or longer, Estimated fair value	41,064	837
Twelve months or longer, Unrealized loss and OTTI	681	239
Total Estimated fair value	59,344	215,816
Total Unrealized losses and OTTI	899	16,952
Foreign government securities
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	2,451	2,603
Less than twelve months, Unrealized loss and OTTI	4	14
Total Estimated fair value	2,451	2,603
Total Unrealized losses and OTTI	4	14
Corporate debt securities
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	836,263	2,632,093
Less than twelve months, Unrealized loss and OTTI	16,775	144,367
Twelve months or longer, Estimated fair value	764,528	511,376
Twelve months or longer, Unrealized loss and OTTI	65,329	79,165
Total Estimated fair value	1,600,791	3,143,469
Total Unrealized losses and OTTI	82,104	223,532
Additional disclosure
Unrealized losses and OTTI over twelve months on securities (as a percent)	79.00%
Corporate debt securities | Non-investment grade
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Twelve months or longer, Unrealized loss and OTTI	9,921
Perpetual debt investments
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Twelve months or longer, Unrealized loss and OTTI	8,899
Asset-backed securities
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	88,312	305,377
Less than twelve months, Unrealized loss and OTTI	849	12,763
Twelve months or longer, Estimated fair value	200,072	305,740
Twelve months or longer, Unrealized loss and OTTI	12,853	16,387
Total Estimated fair value	288,384	611,117
Total Unrealized losses and OTTI	13,702	29,150
Additional disclosure
Unrealized losses and OTTI over twelve months on securities (as a percent)	16.00%
Residential mortgage-backed securities
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	4,663	32,131
Less than twelve months, Unrealized loss and OTTI	11	3,454
Twelve months or longer, Estimated fair value	24,052	1,011
Twelve months or longer, Unrealized loss and OTTI	1,921	19
Total Estimated fair value	28,715	33,142
Total Unrealized losses and OTTI	1,932	3,473
Commercial mortgage-backed securities
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	35,015	177,395
Less than twelve months, Unrealized loss and OTTI	127	6,703
Twelve months or longer, Estimated fair value	57,333	48,825
Twelve months or longer, Unrealized loss and OTTI	972	4,812
Total Estimated fair value	92,348	226,220
Total Unrealized losses and OTTI	1,099	11,515
Collateralized debt obligations
Unrealized losses on fixed maturity and equity investments classified as available-for-sale
Less than twelve months, Estimated fair value	10,465	0
Less than twelve months, Unrealized loss and OTTI	209	0
Twelve months or longer, Estimated fair value	0	12,356
Twelve months or longer, Unrealized loss and OTTI	0	213
Total Estimated fair value	10,465	12,356
Total Unrealized losses and OTTI	$ 209	$ 213