Restructuring and Asset Related Charges 2017 Restructuring Program (Details) - USD ($) $ in Millions		1 Months Ended		2 Months Ended		3 Months Ended														4 Months Ended	8 Months Ended	12 Months Ended
		Sep. 30, 2017	[1]	Aug. 31, 2017		Dec. 31, 2017		Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Predecessor [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net				$ 11	[1]			$ 160		$ 152		$ 394		$ 172		$ (88)		$ 78			$ 323	$ 556	$ 795
Predecessor [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																					313
Payments for Restructuring																					(8)
Asset write-offs																					(279)
Restructuring Reserve				26																	26
Predecessor [Member] | Employee Severance [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																					34
Payments for Restructuring																					(8)
Asset write-offs																					0
Restructuring Reserve				26																	26
Predecessor [Member] | Asset Related Charges [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net	[2]																				279
Payments for Restructuring																					0
Asset write-offs	[2]																				(279)
Restructuring Reserve				$ 0																	$ 0
Successor [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		$ 40				$ 140	[1]													$ 180
Successor [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																				0
Payments for Restructuring																				(7)
Restructuring Reserve						19														19
Successor [Member] | Employee Severance [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																				0
Payments for Restructuring																				(7)
Restructuring Reserve						19														19
Successor [Member] | Asset Related Charges [Member] | 2017 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																				0
Payments for Restructuring																				0
Restructuring Reserve						$ 0														$ 0

[1] See Note 5 for additional information.

[2] 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.