Equity (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 169,756
Income tax benefit (expense)	117,717	$ 375,580
Ending balance	(273,082)
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,179)	(708)
Change in OCI before reclassifications	25	49
Amounts reclassified from AOCI	0	0
Income tax benefit (expense)	(5)	(10)
Ending balance	(1,159)	(669)
Net Unrealized Investment Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	170,935	1,533,767
Change in OCI before reclassifications	(576,192)	(694,704)
Amounts reclassified from AOCI	15,612	(1,093,820)
Income tax benefit (expense)	117,722	375,590
Ending balance	(271,923)	120,833
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	169,756	1,533,059
Change in OCI before reclassifications	(576,167)	(694,655)
Amounts reclassified from AOCI	15,612	(1,093,820)
Income tax benefit (expense)	117,717	375,580
Ending balance	(273,082)	120,164
Cash flow hedges | Net Unrealized Investment Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	25,000	(43,000)
Ending balance	$ 29,000	$ (40,000)