Condensed Consolidated Statements of Changes in Shareholder's Equity - USD ($)	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Deficit)
Beginning Balance at Dec. 31, 2018	$ 3,435,000,000	$ 3,000,000	$ 2,816,000,000	$ 108,000,000	$ 508,000,000
Comprehensive income (loss):
Net income (loss)	257,000,000	0	0	0	257,000,000
Other comprehensive income (loss), after tax	1,121,000,000	0	0	1,121,000,000	0
Comprehensive income (loss)	1,378,000,000
Ending Balance at Sep. 30, 2019	$ 4,417,000,000	$ 3,000,000	$ 2,816,000,000	$ 1,366,000,000	$ 232,000,000
Comprehensive income (loss):
New Accounting Pronouncement or Change in Accounting Principle, Description | Accounting Standards Update 2018-02	—	—	—	137	(137)
Dividends	$ (396,000,000)				$ 396,000,000
Beginning Balance at Jun. 30, 2019	4,094,000,000	$ 3,000,000	$ 2,816,000,000	$ 1,140,000,000	135,000,000
Comprehensive income (loss):
Net income (loss)	97,000,000	0	0	0	97,000,000
Other comprehensive income (loss), after tax	226,000,000	0	0	226,000,000	0
Comprehensive income (loss)	323,000,000
Ending Balance at Sep. 30, 2019	4,417,000,000	3,000,000	2,816,000,000	1,366,000,000	232,000,000
Comprehensive income (loss):
Dividends		0	0	0
Beginning Balance at Dec. 31, 2019	4,443,000,000	3,000,000	2,873,000,000	1,292,000,000	275,000,000
Comprehensive income (loss):
Net income (loss)	33,000,000	0	0	0	33,000,000
Other comprehensive income (loss), after tax	318,000,000	0	0	318,000,000	0
Comprehensive income (loss)	351,000,000
Ending Balance at Sep. 30, 2020	$ 4,492,000,000	$ 3,000,000	$ 2,873,000,000	$ 1,610,000,000	$ 6,000,000
Comprehensive income (loss):
New Accounting Pronouncement or Change in Accounting Principle, Description | Accounting Standards Update 2016-13	(8)	—	—	—	(8)
Dividends	$ (294,000,000)				$ 294,000,000
Beginning Balance at Jun. 30, 2020	4,511,000,000	$ 3,000,000	$ 2,873,000,000	$ 1,535,000,000	100,000,000
Comprehensive income (loss):
Net income (loss)	(94,000,000)	0	0	0	(94,000,000)
Other comprehensive income (loss), after tax	75,000,000	0	0	75,000,000	0
Comprehensive income (loss)	(19,000,000)
Ending Balance at Sep. 30, 2020	$ 4,492,000,000	$ 3,000,000	$ 2,873,000,000	$ 1,610,000,000	$ 6,000,000
Comprehensive income (loss):
New Accounting Pronouncement or Change in Accounting Principle, Description | Accounting Standards Update 2016-13	—	—	—	—	—