Stockholders' Equity Reclassifications out of AOCI (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, 2018	Aug. 31, 2017	Sep. 30, 2018
Successor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold		$ 1,531		$ 3,686		$ 14,202
Income Tax Expense (Benefit)		(23)		12		180
Loss from continuing operations after income taxes		(275)		(4,960)		(4,662)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax		0		(1)		(8)
Successor [Member] | Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold	[1]	0		1		(6)
Income Tax Expense (Benefit)	[2]	0		(1)		1
Loss from continuing operations after income taxes		0		0		(5)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax						(5)
Successor [Member] | Unrealized loss on investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[3]	0				0
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Tax	[2]	0				0
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax		0				0
Successor [Member] | Pension Plan
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax						(3)
Successor [Member] | Pension Plan | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]	0		0		0
Successor [Member] | Pension Plan | Actuarial (Gains) Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]	0		0		(1)
Successor [Member] | Pension Plan | Settlement Gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]	0		(1)		(2)
Successor [Member] | Pension Plan | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax		0		(1)		(3)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Tax	[2]	0		0		0
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax		0		(1)		(3)
Successor [Member] | Other Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax						0
Successor [Member] | Other Benefit Plans | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]	0		0		0
Successor [Member] | Other Benefit Plans | Actuarial (Gains) Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]	0		0		0
Successor [Member] | Other Benefit Plans | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax		0		0		0
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Tax	[2]	0		0		0
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax		$ 0		$ 0		$ 0
Predecessor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold			$ 1,937		$ 10,052
Income Tax Expense (Benefit)			(132)		149
Loss from continuing operations after income taxes			(258)		1,642
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax			84		321
Predecessor [Member] | Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold	[1]		0		(21)
Income Tax Expense (Benefit)	[2]		0		8
Loss from continuing operations after income taxes			0		(13)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax					(13)
Predecessor [Member] | Unrealized loss on investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[3]				(1)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Tax	[2]				0
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax					(1)
Predecessor [Member] | Pension Plan
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax					325
Predecessor [Member] | Pension Plan | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]		(1)		(3)
Predecessor [Member] | Pension Plan | Actuarial (Gains) Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]		127		506
Predecessor [Member] | Pension Plan | Settlement Gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]		0		0
Predecessor [Member] | Pension Plan | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax			126		503
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Tax	[2]		(45)		(178)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax			81		325
Predecessor [Member] | Other Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax					10
Predecessor [Member] | Other Benefit Plans | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]		(11)		(46)
Predecessor [Member] | Other Benefit Plans | Actuarial (Gains) Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax	[4]		15		61
Predecessor [Member] | Other Benefit Plans | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Loss, Current Period, before Tax			4		15
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Tax	[2]		(1)		(5)
Reclassification from Accumulated Other Comprehensive Loss, Current Period, Net of Tax			$ 3		$ 10

[1] Cost of goods sold.

[2] Provision for income taxes from continuing operations.

[3] Sundry income (expense) - net.

[4] These accumulated other comprehensive (loss) income components are included in the computation of net periodic benefit (credit) cost of the company's pension and other benefit plans. See Note 16 for additional information.