CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 65,356,580	$ 63,268,660
Fixed maturities, allowance for credit losses	22,742	0
Fixed maturities, fair value		3,025,790
Equity securities, cost	634,910	534,463
Mortgage loans, securitizations	222,164	4,884
Investment real estate, accumulated depreciation	370	203
Reinsurance allowance, allowance for credit loss	94,168	0
Other intangibles, accumulated amortization	311,734	253,759
Property and equipment, accumulated depreciation	$ 60,631	$ 49,357
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	2,000	2,000
Preferred stock, Liquidation preference	$ 2	$ 2
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	5,000,000	5,000,000
Common stock, shares issued (in shares)	5,000,000	5,000,000
Net unrealized gains (losses) on investments, income tax	$ 942,548	$ (383,311)
Net unrealized gains (losses) on investments with credit losses, tax	(558)
Net unrealized gains (losses) relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax		(7,004)
Accumulated gain (loss) - derivatives, income tax	$ (2,035)	$ (2,123)