Schedule III Supplemental Insurance Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplemental insurance information
Deferred acquisition costs	$ 172,416	$ 177,781
Future policy benefits, losses, claims and expenses	23,453,611	21,788,419
Unearned premium reserves	27,007	39,855
Other policy claims and benefits payable	769,691	769,086
Premium income	422,153	523,216	805,622
Net investment income	1,191,551	1,158,486	1,174,744
Benefits, claims, losses and settlement expenses	1,198,310	1,263,962	1,540,407
Amortization of deferred acquisition costs	51,434	25,184	27,505
Other operating expenses	643,081	607,791	570,152
Individual Markets Segment
Supplemental insurance information
Deferred acquisition costs	118,490	102,598
Future policy benefits, losses, claims and expenses	13,593,217	12,812,079
Unearned premium reserves	27,007	39,855
Other policy claims and benefits payable	744,504	742,457
Premium income	314,350	395,923	676,395
Net investment income	729,885	714,228	730,439
Benefits, claims, losses and settlement expenses	882,726	937,885	1,218,791
Amortization of deferred acquisition costs	28,926	10,497	20,448
Other operating expenses	107,969	98,509	113,997
Retirement Services Segment
Supplemental insurance information
Deferred acquisition costs	53,926	75,183
Future policy benefits, losses, claims and expenses	9,491,094	8,620,044
Other policy claims and benefits payable	476	445
Premium income	3,670	1,960	5,509
Net investment income	414,114	399,222	399,456
Benefits, claims, losses and settlement expenses	204,296	222,643	221,943
Amortization of deferred acquisition costs	22,508	14,687	7,057
Other operating expenses	469,919	420,461	394,060
Other Segment
Supplemental insurance information
Future policy benefits, losses, claims and expenses	369,300	356,296
Other policy claims and benefits payable	24,711	26,184
Premium income	104,133	125,333	123,718
Net investment income	47,552	45,036	44,849
Benefits, claims, losses and settlement expenses	111,288	103,434	99,673
Other operating expenses	$ 65,193	$ 88,821	$ 62,095