Income Taxes (Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current tax expense (benefit):
U.S. federal	$ 241,355	$ 91,707	$ 14,381
State and local	2,588	0	0
Total	243,943	91,707	14,381
Deferred tax expense (benefit):
U.S. federal	1,050,062	(957,427)	(305,482)
Total	1,050,062	(957,427)	(305,482)
Income tax expense (benefit)	1,294,005	(865,720)	(291,101)
Total income tax expense (benefit) reported in equity related to:
Other comprehensive income (loss)	(362,398)	293,588	200,447
Total income tax expense (benefit)	$ 931,607	$ (572,132)	$ (90,654)