Policy Liabilities - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Liability for Future Policy Benefit, Activity [Line Items]
Change in assumptions of lapse, mortality, and morbidity, remeasurement gain (loss)	$ 3,200	$ (36,500)	$ (4,100)
Change in expected experience, remeasurement gain (loss)	38,000	4,600	8,200
Life
Liability for Future Policy Benefit, Activity [Line Items]
Change in assumptions of lapse, mortality, and morbidity, remeasurement gain (loss)	(2,000)	(47,200)	(4,100)
Change in expected experience, remeasurement gain (loss)	31,400	(272)	(7,000)
PV of expected future gross premiums	28,899,367	27,077,677	32,900,586
PV of expected future net premiums	12,342,307	11,748,528	14,082,538	$ 13,425,359
Health
Liability for Future Policy Benefit, Activity [Line Items]
Change in assumptions of lapse, mortality, and morbidity, remeasurement gain (loss)	5,200	10,700	0
Change in expected experience, remeasurement gain (loss)	6,600	4,900	1,200
PV of expected future gross premiums	11,834,715	10,334,511	12,354,670
PV of expected future net premiums	$ 6,089,728	$ 5,207,422	$ 6,418,018	$ 6,240,414