Assets By Segment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and invested assets	$ 14,155,919	$ 12,437,699
Accrued investment income	195,497	192,325
Deferred acquisition costs	3,198,431	2,916,732
Goodwill	441,591	396,891
Other assets	785,472	644,625
Total assets	18,776,910	16,588,272
Life Insurance
Segment Reporting, Asset Reconciling Item [Line Items]
Deferred acquisition costs	2,688,876	2,566,748
Goodwill	309,609	309,609
Total assets	2,998,485	2,876,357
Health Insurance
Segment Reporting, Asset Reconciling Item [Line Items]
Deferred acquisition costs	481,725	315,587
Goodwill	131,982	87,282
Total assets	613,707	402,869
Annuity
Segment Reporting, Asset Reconciling Item [Line Items]
Deferred acquisition costs	27,830	34,397
Total assets	27,830	34,397
Investment
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and invested assets	14,155,919	12,437,699
Accrued investment income	195,497	192,325
Total assets	14,351,416	12,630,024
All Other Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Other assets	785,472	644,625
Total assets	$ 785,472	$ 644,625