Equity (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			$ 347,435
Income tax benefit (expense)	$ 189,054	$ (45,396)	402,512	$ 28,335
Ending Balance	(1,171,582)		(1,171,582)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(11,274)	(7,797)
Change in OCI before reclassifications			(7,870)	(4,781)
Amounts reclassified from AOCI			0	0
Income tax benefit (expense)			735	149
Ending Balance	(18,409)	(12,429)	(18,409)	(12,429)
Net unrealized investment gains (losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			358,709	553,925
Change in OCI before reclassifications			(1,920,685)	(129,762)
Amounts reclassified from AOCI			7,026	(4,473)
Income tax benefit (expense)			401,777	28,186
Ending Balance	(1,153,173)	447,876	(1,153,173)	447,876
Accumulated Other Comprehensive   Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			347,435	546,128
Change in OCI before reclassifications			(1,928,555)	(134,543)
Amounts reclassified from AOCI			7,026	(4,473)
Income tax benefit (expense)			402,512	28,335
Ending Balance	(1,171,582)	435,447	(1,171,582)	435,447
Cash flow hedges | Net unrealized investment gains (losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			40,000	(8,000)
Ending Balance	$ 144,000	$ 12,000	$ 144,000	$ 12,000