Industry Segments (Identifiable Assets by Segment) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		$ 21,689,809	$ 21,679,239
Operating Segments [Member] | Reinsurance-Global Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		2,532,001	2,708,090
Operating Segments [Member] | Insurance-International Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		1,854,074	1,876,347
Operating Segments [Member] | Insurance-Domestic Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		16,105,299	16,036,513
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	[1]	$ 1,198,435	$ 1,058,289

[1] Corporate and eliminations represent corporate revenues and expenses that are not allocated to business segments.