Unaudited Interim Statements of Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Cumulative effect of adoption of accounting changes	[1]	Cumulative effect of adoption of accounting changes Retained Earnings (Accumulated Deficit)	[1]
Beginning Balance at Dec. 31, 2019	$ 5,527,355	$ 2,500	$ 5,142,936	$ (46,693)	$ 428,612	$ (1,392)		$ (1,392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital	(207,000)		(207,000)
Dividend to parent	0
Comprehensive income:
Net income (loss)	(820,788)			(820,788)
Other comprehensive income (loss), net of tax	1,010,888				1,010,888
Total comprehensive income (loss)	190,100
Ending Balance at Mar. 31, 2020	5,509,063	2,500	4,935,936	(868,873)	1,439,500
Beginning Balance at Dec. 31, 2019	5,527,355	2,500	5,142,936	(46,693)	428,612	$ (1,392)		$ (1,392)
Comprehensive income:
Net income (loss)	(2,577,002)
Other comprehensive income (loss), net of tax	1,206,320
Ending Balance at Jun. 30, 2020	3,775,281	2,500	4,762,936	(2,625,087)	1,634,932
Beginning Balance at Mar. 31, 2020	5,509,063	2,500	4,935,936	(868,873)	1,439,500
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital	(173,000)		(173,000)
Dividend to parent	0
Comprehensive income:
Net income (loss)	(1,756,214)			(1,756,214)
Other comprehensive income (loss), net of tax	195,432				195,432
Total comprehensive income (loss)	(1,560,782)
Ending Balance at Jun. 30, 2020	3,775,281	2,500	4,762,936	(2,625,087)	1,634,932
Beginning Balance at Dec. 31, 2020	2,701,145	2,500	4,382,936	(3,217,350)	1,533,059
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital	0		0
Dividend to parent	(192,000)			(192,000)
Comprehensive income:
Net income (loss)	1,889,813			1,889,813
Other comprehensive income (loss), net of tax	(1,412,895)				(1,412,895)
Total comprehensive income (loss)	476,918
Ending Balance at Mar. 31, 2021	2,986,063	2,500	4,382,936	(1,519,537)	120,164
Beginning Balance at Dec. 31, 2020	2,701,145	2,500	4,382,936	(3,217,350)	1,533,059
Comprehensive income:
Net income (loss)	1,815,213
Other comprehensive income (loss), net of tax	(1,178,793)
Ending Balance at Jun. 30, 2021	2,957,565	2,500	4,382,936	(1,782,137)	354,266
Beginning Balance at Mar. 31, 2021	2,986,063	2,500	4,382,936	(1,519,537)	120,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital	0		0
Dividend to parent	(188,000)			(188,000)
Comprehensive income:
Net income (loss)	(74,600)			(74,600)
Other comprehensive income (loss), net of tax	234,102				234,102
Total comprehensive income (loss)	159,502
Ending Balance at Jun. 30, 2021	$ 2,957,565	$ 2,500	$ 4,382,936	$ (1,782,137)	$ 354,266

[1] Includes the impact from the adoption of ASU 2016-13. See Note 2 to the Financial Statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2020 for additional information.