Derivatives - Statements of Earnings (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Increase (decrease) in contract interest expense	$ 0	$ 2,100	$ 0	$ 6,500
Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives	95,746	(6,683)	187,757	60,445
Derivatives not designated as hedging instruments | Equity index options
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives	(38,425)	40,166	(76,623)	68,190
Derivatives not designated as hedging instruments | Fixed-index products
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives	39,187	(48,819)	78,491	(80,085)
Derivatives not designated as hedging instruments | Embedded derivative on reinsurance contract
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives	$ 94,984	$ 1,970	$ 185,889	$ 72,340