Industry Segments (Identifiable Assets by Segment) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	$ 20,704,267		$ 20,551,796
Operating Segments [Member] | Reinsurance-Global Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	2,835,292		3,103,193
Operating Segments [Member] | Insurance-International Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	1,805,842		1,516,310
Operating Segments [Member] | Insurance-Domestic Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	15,177,789		15,247,807
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	$ 885,344	[1]	$ 684,486	[1]

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjg3ZTg4YTYzZTE5OTQ1MGQ5ZGZjMjQ0Y2JjYzAxNDY3fFRleHRTZWxlY3Rpb246MDdDNkE3ODY2NzRGNURFQjkyQThGM0M0Q0Q0QjlCOEUM}