Income Taxes Level 4 (Details) - Reconciliation of Differences Between Income Taxes For Continuing Operations and Provisions for Income Taxes - USD ($) $ in Millions		6 Months Ended		12 Months Ended
		Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2018
Income Taxes Reconciliation between Continuing Operations and Provisions for Income Taxes [Line Items]
Income tax (benefit) expense computed at federal statutory tax rate		$ (21)	$ 622	$ (31)	$ (35)
State tax (benefit) expense, net of federal benefit		(2)	9	(5)	1
Foreign tax rate expense differential		2	33	1	13
Foreign source income subject to U.S. taxation		3	1	0	2
Non-deductible losses and other expenses		0	5	0	9
Increase (decrease) in the taxes due to changes in valuation allowance		17	(433)	46	25
Additional (benefit) expense on foreign unrepatriated earnings		0	0	(3)	(1)
Additional expense for uncertain tax positions		0	44	(4)	15
Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Amount		(1)	(4)	0	0
Changes in enacted tax laws and tax rates		0	0	6	0
Effective income tax rate reconciliation, Fresh start and reorganization adjustment impact		0	(68)	0	0
write off net operating loss		(8)	(8)	4	0
Income tax expense (benefit) (1)	[1]	$ (10)	$ 201	$ 14	$ 31

[1] Excludes income tax expense of $1, $1, $21, and $9 for the year ended December 31, 2020, the Successor period July 2, 2019 through December 31, 2019, the Predecessor period January 1, 2019 through July 1, 2019, and the year ended December 31, 2018, respectively, related to the Held for Sale Business.