CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	Reorganization Adjustments
Balance, beginning balance at Dec. 31, 2016	$ 2,068	$ 1	$ 6,571	$ (2,950)	$ (1,610)	$ 56
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(2,793)			(2,813)		20
Other Comprehensive Loss	91				91
Dividends Paid to Noncontrolling Interests	(21)					(21)
Equity Awards Granted, Vested and Exercised	(84)	0	(84)
Balance, ending balance at Dec. 31, 2017	(571)	1	6,655	(5,763)	(1,519)	55
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(2,791)			(2,811)		20
Other Comprehensive Loss	(227)				(227)
Dividends Paid to Noncontrolling Interests	(16)					(16)
Equity Awards Granted, Vested and Exercised	(52)	0	(52)
Stockholders' Equity, Other	(16)		(4)			(20)
Balance, ending balance at Dec. 31, 2018	(3,666)	1	6,711	(8,671)	(1,746)	39
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	(97)			(97)
Temporary Equity, Elimination as Part of Reorganization	(1,697)
Net Income (Loss)	3,684	0	0	3,661	0	23
Other Comprehensive Loss	49				49
Dividends Paid to Noncontrolling Interests	(22)					(22)
Equity Awards Granted, Vested and Exercised	(22)		(22)
Accelerated Stock Compensation due to Plan Effects	24		24
Stockholders' Equity, Other	2		0			2
Balance, ending balance at Dec. 13, 2019	2,931	0	2,897	0	0	34
Fresh-Start Adjustment, Issuance Of Common Stock To Former Stockholders							$ 29
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fresh-Start Adjustment, Issuance Of Warrants							31
Temporary Equity, Elimination as Part of Reorganization	(51)	1		(5,010)	(1,697)	0	6,757
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	2,837
Stockholders' Equity, Other	8		0			(8)
Balance, ending balance at Dec. 13, 2019	2,931	0	2,897	0	0	34
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Shares to Prior Shareholders	29
Adjustments to Additional Paid in Capital, Warrant Issued	31
Fresh-Start Adjustment, Issuance Of Successor Common Stock To Creditors							2,837
Fresh-Start Adjustment, Issuance Of Common Stock To Former Stockholders							29
Fresh-Start Adjustment, Issuance Of Warrants							$ 31
Net Income (Loss)	(24)			(26)		2
Other Comprehensive Loss	9				9
Balance, ending balance at Dec. 31, 2019	$ 2,916	$ 0	$ 2,897	$ (26)	$ 9	$ 36