Statements of Equity - USD ($) $ in Thousands	Total	Common   Stock	Additional   Paid-in Capital	Additional   Paid-in Capital Transferred to/from Affiliates	Retained Earnings/  (Accumulated Deficit)	Retained Earnings/  (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment		Accumulated Other Comprehensive   Income (Loss)	Total Equity	Total Equity   Transferred to/from Affiliates	Total Equity   Cumulative Effect, Period of Adoption, Adjustment
Beginning Balance at Dec. 31, 2018		$ 2,500	$ 6,120,436		$ 943,005	$ (371)	[1]	$ (324,373)	$ 6,741,568		$ (371)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital			(977,500)						(977,500)
Dividend to parent									0
Assets purchased/transferred from/to affiliates										$ 0
Comprehensive income (loss):
Net income (loss)	$ (989,327)				(989,327)				(989,327)
Other comprehensive income (loss), net of tax	752,985							752,985	752,985
Total comprehensive income (loss)									(236,342)
Ending Balance at Dec. 31, 2019		2,500	5,142,936		(46,693)	$ (1,392)	[2]	428,612	5,527,355		$ (1,392)	[2]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital			(760,000)						(760,000)
Dividend to parent									0
Assets purchased/transferred from/to affiliates										0
Comprehensive income (loss):
Net income (loss)	(3,169,265)				(3,169,265)				(3,169,265)
Other comprehensive income (loss), net of tax	1,104,447							1,104,447	1,104,447
Total comprehensive income (loss)									(2,064,818)
Ending Balance at Dec. 31, 2020		2,500	4,382,936		(3,217,350)			1,533,059	2,701,145
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital			(3,813,369)						(3,813,369)
Dividend to parent					(830,748)				(830,748)
Assets purchased/transferred from/to affiliates				$ 22,641						$ 22,641
Comprehensive income (loss):
Net income (loss)	4,965,361				4,965,361				4,965,361
Other comprehensive income (loss), net of tax	$ (1,363,303)							(1,363,303)	(1,363,303)
Total comprehensive income (loss)									3,602,058
Ending Balance at Dec. 31, 2021		$ 2,500	$ 592,208		$ 917,263			$ 169,756	$ 1,681,727

[1] Includes the impact from the adoption of ASU 2017-08 and 2017-12.

[2] Includes the impact from the adoption of ASU 2016-13. See Note 2.