Components of Pension and OPEB expense (Details) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
		Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2018
Other Postretirement Benefits Plan [Member] | UNITED STATES
Pension Benefits and Non-Pension Postretirement Benefits Disclosures Table Text Block [Line Items]
Interest cost		$ 0	$ 0	$ 0	$ 0
Unrealized actuarial loss(1)	[1]	0	0	0	0
Net expense (benefit)		0	0	0	0
Other Postretirement Benefits Plan [Member] | Foreign Plan [Member]
Pension Benefits and Non-Pension Postretirement Benefits Disclosures Table Text Block [Line Items]
Interest cost		0	0	1	1
Unrealized actuarial loss(1)	[1]	(4)	4	(1)	2
Net expense (benefit)		(4)	4	0	3
Pension Plan [Member] | UNITED STATES
Pension Benefits and Non-Pension Postretirement Benefits Disclosures Table Text Block [Line Items]
Service cost		2	2	2	3
Interest cost		3	4	6	7
Expected return on assets		(7)	(6)	(12)	(14)
Unrealized actuarial loss(1)		0	1	11	11
Net expense (benefit)		(2)	1	7	7
Pension Plan [Member] | UNITED STATES | Discontinued Operations
Pension Benefits and Non-Pension Postretirement Benefits Disclosures Table Text Block [Line Items]
Net expense (benefit)		0	0	0	0
Pension Plan [Member] | Foreign Plan [Member]
Pension Benefits and Non-Pension Postretirement Benefits Disclosures Table Text Block [Line Items]
Service cost		8	7	18	17
Interest cost		4	4	6	10
Expected return on assets		(6)	(6)	(13)	(13)
Unrealized actuarial loss(1)	[1]	9	39	(2)	(26)
Net expense (benefit)	[2]	15	44	9	(12)
Pension Plan [Member] | Foreign Plan [Member] | Discontinued Operations
Pension Benefits and Non-Pension Postretirement Benefits Disclosures Table Text Block [Line Items]
Net expense (benefit)		$ 1	$ 6	$ 5	$ 1

[1] Upon the application of fresh start accounting, the Company’s pension and other non-pension postretirement liabilities were remeasured as of the Predecessor period July 1, 2019. As a result, for the Predecessor period January 1, 2019 through July 1, 2019, total unrealized actuarial losses of $44 were recorded to “Reorganization, net” in the Consolidated Statements of Operations, $5 of which relate to the Company’s Held for Sale business.

[2] Net expense (benefit) related to the Company’s Held for Sale Business was $5, $<1, $6 and $1 for the year ended December 31, 2020, the Successor period from July 2, 2019 to December 31, 2019, the Predecessor period from January 1, 2019 through July 1, 2020 and the year ended December 31, 2018, respectively, and is included in the table above.