Industry Segments (Identifiable Assets by Segment) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	$ 22,097,597		$ 20,551,796
Operating Segments [Member] | Reinsurance-Global Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	2,801,268		3,103,193
Operating Segments [Member] | Insurance-International Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	1,915,322		1,516,310
Operating Segments [Member] | Insurance-Domestic Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	16,074,387		15,247,807
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	$ 1,306,620	[1]	$ 684,486	[1]

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