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]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2018	$ 1,633	$ 1,421	$ (49)	$ 0	$ 0	$ 219	$ 0	$ 41
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(30)	(106)	75	0	0	0	0	0
Stock-based compensation	10	0	0	0	0	10	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(3)	(3)	0	0	0	0	0	0
Ending balance at Sep. 30, 2019	1,629	1,313	26	0	0	229	0	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AMPS Impact on Stockholders Equity	19	0	0	0	0	0	0	19
Beginning balance at Jun. 30, 2019	1,553	1,247	19	0	0	227	0	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	73	66	7	0	0	0	0	0
Stock-based compensation	2	0	0	0	0	2	0	0
Ending balance at Sep. 30, 2019	1,629	1,313	26	0	0	229	0	60
Beginning balance at Dec. 31, 2019	1,536	1,203	42	0	0	232	0	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(442)	(423)	(20)	0	0	0	0	0
Stock-based compensation	8	0	0	0	0	8	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(3)	(2)	0	0	0	0	(1)	0
Ending balance at Sep. 30, 2020	1,095	773	22	0	0	240	(1)	60
Beginning balance at Jun. 30, 2020	1,129	881	(48)	0	0	237	(1)	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(37)	(108)	71	0	0	0	0	0
Stock-based compensation	3	0	0	0	0	3	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0	0	0	0	0	0
Ending balance at Sep. 30, 2020	1,095	773	22	$ 0	$ 0	$ 240	$ (1)	$ 60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-13 [Member]	$ (4)	$ (4)	$ 0