Restructuring and Asset Related Charges - Net (2017 Restructuring Program schedule) (Details) - USD ($) $ in Millions		1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
		Sep. 30, 2017	Aug. 31, 2017	Sep. 30, 2016	Aug. 31, 2017	Sep. 30, 2016
Predecessor
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net			$ 11	$ 172	$ 323	$ 162
Predecessor | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net					313
Payments for Restructuring					(8)
Restructuring reserve, asset write-offs					(279)
Restructuring Reserve			26		26
Predecessor | Severance and Related Benefit Costs [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net			1		34
Payments for Restructuring					(8)
Restructuring reserve, asset write-offs					0
Restructuring Reserve			26		26
Predecessor | Asset Related Charges [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net	[1]				279
Payments for Restructuring	[1]				0
Restructuring reserve, asset write-offs	[1]				(279)
Restructuring Reserve	[1]		$ 0		$ 0
Successor
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		$ 40
Successor | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		0
Payments for Restructuring		(1)
Restructuring Reserve		25
Successor | Severance and Related Benefit Costs [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		0
Payments for Restructuring		(1)
Restructuring Reserve		25
Successor | Asset Related Charges [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net	[1]	0
Payments for Restructuring	[1]	0
Restructuring Reserve	[1]	$ 0

[1] Includes accelerated depreciation related to site closure. Charge for accelerated depreciation represents the difference between the depreciation expense to be recognized over the revised useful life of the site, based upon the anticipated date the site will be closed and depreciation expense as determined utilizing the useful life prior to the restructuring action.