Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Common Stock Held in Treasury, at Cost [Member]	Noncontrolling Interest [Member]	Parent Company [Member]	Parent Company [Member] Retained Earnings [Member]	Parent Company [Member] AOCI Attributable to Parent [Member]	Parent Company [Member] Additional Paid-in Capital [Member]	Parent Company [Member] Common Stock Held in Treasury, at Cost [Member]
Beginning balance at Dec. 31, 2017	$ 1,645	$ 1,234	$ (52)	$ 0	$ 0	$ 200	$ 0	$ 264
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	274	267	6	0	0	0	0	0	$ 192	$ 186	$ 6
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	0								0
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2016-01 [Member]		3	(3)
Cost of warrants acquired	12	0	0	0	0	12	0	0	12			$ 12
Issuance of common stock	(1)	(1)	0	0	0	0	0	0	(1)	(1)			$ 0
Ending balance at Dec. 31, 2018	1,633	1,421	(49)	0	0	219	0	41
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AMPS Impact on Stockholders Equity	(297)	(82)	0	0	0	8	0	(223)	8			8
Total comprehensive income (loss)	(125)	(216)	91	0	0	0	0	0	(125)	(216)	91
Cost of warrants acquired	12	0	0	0	0	12	0	0	12			12	0
Issuance of common stock	(3)	(3)	0	0	0	0	0	0	(3)	(3)			0
Ending balance at Dec. 31, 2019	1,536	1,203	42	0	0	232	0	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AMPS Impact on Stockholders Equity	19	0	0	0	0	0	0	19
Redeemable Noncontrolling Interest, Equity, Other, Fair Value	0
Total comprehensive income (loss)	(400)	(437)	37	0	0	0	0	0	(400)	(437)	$ 37
Cost of warrants acquired	11	0	0	0	0	11	0	0	11			$ 11
Issuance of common stock	(3)	(2)	0	0	0	0	(1)	0	$ (3)	$ (2)			$ (1)
Ending balance at Dec. 31, 2020	1,140	759	$ 79	$ 0	$ 0	$ 242	$ (1)	$ 60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	7
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-13 [Member]	(4)	$ (4)
Redeemable Noncontrolling Interest, Equity, Other, Fair Value	$ 7