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)	28	(43)	71	0	0	0	0	0
Stock-based compensation	4	0	0	0	0	4	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(2)	(2)	0	0	0	0	0	0
AMPS Impact on Stockholders Equity	3	0	0	0	0	0	0	3
Ending balance at Mar. 31, 2019	1,666	1,376	23	0	0	224	(1)	44
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)	(470)	(280)	(191)	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	(3)	(1)	0	0	0	0	(1)	0
Ending balance at Mar. 31, 2020	$ 1,062	$ 917	$ (149)	$ 0	$ 0	$ 235	$ (2)	$ 60