Supplemental Information about Changes to Accumulated Other Comprehensive Income - Schedule of Change in Balance by Component (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (Decrease) in AOCI, Net of Tax
Beginning balance	$ 3,846,291	$ 2,544,275	$ 3,949,577	$ 2,003,808
Other comprehensive income (loss) before reclassifications, net of tax	(21,593)	578,678	(218,082)	987,189
Reclassifications, net of tax	38,789	20,303	64,498	19,834
Other comprehensive income (loss)	17,196	598,981	(153,584)	1,007,023
Ending balance	3,980,306	3,220,303	3,980,306	3,220,303
Total
Increase (Decrease) in AOCI, Net of Tax
Beginning balance	(2,961,093)	(3,827,006)	(2,790,313)	(4,235,048)
Ending balance	(2,943,897)	(3,228,025)	(2,943,897)	(3,228,025)
Available for Sale Assets
Increase (Decrease) in AOCI, Net of Tax
Beginning balance	(1,016,764)	950,921	(1,420,672)	2,765,290
Other comprehensive income (loss) before reclassifications, net of tax	(271,681)	(1,611,891)	106,481	(3,423,076)
Reclassifications, net of tax	39,046	17,585	64,792	14,401
Other comprehensive income (loss)	(232,635)	(1,594,306)	171,273	(3,408,675)
Ending balance	(1,249,399)	(643,385)	(1,249,399)	(643,385)
Future Policy Benefits
Increase (Decrease) in AOCI, Net of Tax
Beginning balance	(1,938,707)	(4,699,555)	(1,369,204)	(6,915,910)
Other comprehensive income (loss) before reclassifications, net of tax	241,906	2,205,113	(327,597)	4,421,468
Reclassifications, net of tax	0	0	0	0
Other comprehensive income (loss)	241,906	2,205,113	(327,597)	4,421,468
Ending balance	(1,696,801)	(2,494,442)	(1,696,801)	(2,494,442)
Foreign Exchange
Increase (Decrease) in AOCI, Net of Tax
Beginning balance	(6,829)	22,589	(1,681)	19,248
Other comprehensive income (loss) before reclassifications, net of tax	8,182	(14,544)	3,034	(11,203)
Reclassifications, net of tax	0	0	0	0
Other comprehensive income (loss)	8,182	(14,544)	3,034	(11,203)
Ending balance	1,353	8,045	1,353	8,045
Pension Adjustments
Increase (Decrease) in AOCI, Net of Tax
Beginning balance	1,207	(100,961)	1,244	(103,676)
Other comprehensive income (loss) before reclassifications, net of tax	0	0	0	0
Reclassifications, net of tax	(257)	2,718	(294)	5,433
Other comprehensive income (loss)	(257)	2,718	(294)	5,433
Ending balance	$ 950	$ (98,243)	$ 950	$ (98,243)