Business Segments - Schedule of Assets by Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Segment Reporting, Asset Reconciling Item [Line Items]
Accrued investment income	$ 287,562	$ 269,791
Deferred acquisition costs	6,623,644	6,495,589	$ 6,131,237
Goodwill	490,446	490,446
Total assets	29,705,259	29,076,181
Life
Segment Reporting, Asset Reconciling Item [Line Items]
Deferred acquisition costs	5,814,820	5,700,755	5,378,825	$ 5,271,775
Health
Segment Reporting, Asset Reconciling Item [Line Items]
Deferred acquisition costs	807,773	793,421	$ 749,844	$ 734,735
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and invested assets	20,242,276	19,736,888
Accrued investment income	287,562	269,791
Deferred acquisition costs	6,622,593	6,494,176
Goodwill	490,446	490,446
Total segment assets	27,642,877	26,991,301
Operating Segments | Life
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and invested assets	0	0
Accrued investment income	0	0
Deferred acquisition costs	5,814,820	5,700,755
Goodwill	309,609	309,609
Total segment assets	6,124,429	6,010,364
Operating Segments | Health
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and invested assets	0	0
Accrued investment income	0	0
Deferred acquisition costs	807,773	793,421
Goodwill	180,837	180,837
Total segment assets	988,610	974,258
Operating Segments | Investment
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and invested assets	20,242,276	19,736,888
Accrued investment income	287,562	269,791
Deferred acquisition costs	0	0
Goodwill	0	0
Total segment assets	20,529,838	20,006,679
Corporate & Other
Segment Reporting, Asset Reconciling Item [Line Items]
Annuity and other corporate	$ 2,062,382	$ 2,084,880