Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 970,755	$ 894,386	$ 1,031,114
Unrealized gains (losses) on fixed maturities:
Unrealized holding gains (losses) arising during period	671,211	(5,332,818)	(492,267)
Other reclassification adjustments included in net income	80,238	32,377	(31,710)
Foreign exchange adjustment on fixed maturities recorded at fair value	(715)	1,749	4,632
Total unrealized investment gains (losses)	750,734	(5,298,692)	(519,345)
Less applicable tax (expense) benefit	(157,658)	1,112,730	109,063
Unrealized gains (losses) on investments, net of tax	593,076	(4,185,962)	(410,282)
Future Policy benefits:
Change in discount rate on future policy benefits	(731,883)	7,021,147	1,156,763
Less applicable tax (expense) benefit	153,696	(1,474,441)	(242,920)
Future policy benefit adjustments, net of tax	(578,187)	5,546,706	913,843
Foreign exchange translation:
Foreign exchange translation adjustments, other than securities	8,102	(26,494)	(5,131)
Less applicable tax (expense) benefit	(1,702)	5,565	1,077
Foreign exchange translation adjustments, other than securities, net of tax	6,400	(20,929)	(4,054)
Pension:
Amortization of pension costs	(390)	13,754	20,797
Plan amendments	0	0	(4,565)
Experience gain (loss)	(3,907)	119,055	61,299
Pension adjustments	(4,297)	132,809	77,531
Less applicable tax (expense) benefit	902	(27,889)	(16,281)
Pension adjustments, net of tax	(3,395)	104,920	61,250
Other comprehensive income (loss)	17,894	1,444,735	560,757
Comprehensive income (loss)	$ 988,649	$ 2,339,121	$ 1,591,871