SCHEDULE III - Supplementary Insurance Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Supplementary Insurance Information By Segment [Line Items]
Deferred Policy Acquisition Costs	$ 568,391		$ 547,202		$ 595,557
Gross Reserves	10,709,371		11,273,091		10,666,604
Unearned Premiums	1,534,625		1,448,841		1,599,139
Other Benefits Payable	1,813,244		1,645,662		1,750,410
Premium Revenue	4,485,939		4,647,754		4,776,471
Net Investment Income	571,338	[1]	629,148	[1]	672,782	[1]
Losses Incurred	2,804,610		4,372,570		3,283,618
Amortization of DAC	936,909		938,361		972,537
Other Operating Expenses	411,374	[2]	434,846	[2]	539,751	[2]
Premiums Written	3,774,474		3,700,575		3,962,677
[LifeMember]
Supplementary Insurance Information By Segment [Line Items]
Deferred Policy Acquisition Costs	205,203		208,108		226,476
Gross Reserves	0		0		0
Unearned Premiums	17,267		15,316		20,385
Other Benefits Payable	1,813,244		1,645,662		1,750,410
Premium Revenue	794,598		792,148		743,565
Net Investment Income	64,223	[1]	66,069	[1]	71,539	[1]
Losses Incurred	646,981		650,261		623,627
Amortization of DAC	115,887		116,884		116,280
Other Operating Expenses	52,352	[2]	52,905	[2]	56,965	[2]
[NonLifeMember]
Supplementary Insurance Information By Segment [Line Items]
Deferred Policy Acquisition Costs	363,174		339,010		369,075
Gross Reserves	10,709,371		11,273,091		10,666,604
Unearned Premiums	1,517,217		1,432,476		1,578,696
Other Benefits Payable	0		0		0
Premium Revenue	3,684,069		3,844,270		4,029,644
Losses Incurred	2,155,147		3,717,171		2,657,041
Amortization of DAC	820,464		820,747		856,068
Other Operating Expenses	257,256	[2]	283,450	[2]	316,900	[2]
Premiums Written	3,768,111		3,688,185		3,960,713
[CorporateAndOtherMember]
Supplementary Insurance Information By Segment [Line Items]
Deferred Policy Acquisition Costs	14		84		6
Gross Reserves	0		0		0
Unearned Premiums	141		1,049		58
Other Benefits Payable	0		0		0
Premium Revenue	7,272		11,336		3,262
Net Investment Income	507,115	[1]	563,079	[1]	601,243	[1]
Losses Incurred	2,482		5,138		2,950
Amortization of DAC	558		730		189
Other Operating Expenses	101,766	[2]	98,491	[2]	165,886	[2]
Premiums Written	$ 6,363		$ 12,390		$ 1,964

[1] Because the Company does not manage its assets by segment, net investment income is not allocated to the Non-life segment of the reinsurance operations. However, because of the interest-sensitive nature of some of the Company’s Life products, net investment income is considered in Management’s assessment of the profitability of the Life segment.

[2] Other operating expenses are a component of underwriting result for the Non-life and Life segments. Other operating expenses included in Corporate and Other represent corporate expenses and other operating expenses related to the Company’s principal finance transactions, insurance-linked securities and strategic investments.