Industry Segments (Identifiable Assets by Segment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	$ 21,716,691	$ 20,551,796
Operating Segments | Insurance-Domestic
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	16,065,409	15,247,807
Operating Segments | Insurance-International
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	1,879,438	1,516,310
Operating Segments | Reinsurance-Global
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	2,713,554	3,103,193
Corporate, Other and Eliminations Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	$ 1,058,290	$ 684,486	[1]

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