Stockholders' Equity Reclassifications out of AOCI (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	[1]	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold		$ 1,511			$ 4,654								$ 6,165
Income Tax Expense (Benefit)													(2,673)
Income from continuing operations after income taxes													1,087
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													0
Successor [Member] | Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold	[2]												0
Income Tax Expense (Benefit)	[3]												0
Income from continuing operations after income taxes													0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													0
Successor [Member] | Unrealized gain (loss) on investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[4]												0
Reclassification from AOCI, Current Period, Tax	[3]												0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													0
Predecessor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold				$ 1,975			$ 4,021	$ 4,209	$ 3,032	$ 2,997	$ 3,823	$ 4,103		$ 10,205	$ 13,955	$ 14,591
Income Tax Expense (Benefit)														149	641	575
Income from continuing operations after income taxes														1,642	2,082	1,447
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														321	335	297
Predecessor [Member] | Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of Goods Sold	[2]													(21)	18	12
Income Tax Expense (Benefit)	[3]													8	(7)	(5)
Income from continuing operations after income taxes														(13)	11	7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														(13)	11	7
Predecessor [Member] | Unrealized gain (loss) on investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[4]													(1)	28	(2)
Reclassification from AOCI, Current Period, Tax	[3]													0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														(1)	28	(2)
Pension Plan | Successor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													0
Pension Plan | Successor [Member] | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Pension Plan | Successor [Member] | Actuarial Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Pension Plan | Successor [Member] | Curtailment (loss) gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Pension Plan | Successor [Member] | Settlement loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Pension Plan | Successor [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax													0
Reclassification from AOCI, Current Period, Tax	[3]												0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													0
Pension Plan | Predecessor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														325	594	535
Pension Plan | Predecessor [Member] | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													(3)	(6)	(9)
Pension Plan | Predecessor [Member] | Actuarial Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													506	822	768
Pension Plan | Predecessor [Member] | Curtailment (loss) gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													0	40	(6)
Pension Plan | Predecessor [Member] | Settlement loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													0	62	76
Pension Plan | Predecessor [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax														503	918	829
Reclassification from AOCI, Current Period, Tax	[3]													(178)	(324)	(294)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														325	594	535
Other Benefit Plans | Successor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													0
Other Benefit Plans | Successor [Member] | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Other Benefit Plans | Successor [Member] | Actuarial Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Other Benefit Plans | Successor [Member] | Curtailment (loss) gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]												0
Other Benefit Plans | Successor [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax													0
Reclassification from AOCI, Current Period, Tax	[3]												0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax													$ 0
Other Benefit Plans | Predecessor [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														10	(298)	(243)
Other Benefit Plans | Predecessor [Member] | Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													(46)	(134)	(182)
Other Benefit Plans | Predecessor [Member] | Actuarial Losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													61	78	78
Other Benefit Plans | Predecessor [Member] | Curtailment (loss) gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[5]													0	(392)	(274)
Other Benefit Plans | Predecessor [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax														15	(448)	(378)
Reclassification from AOCI, Current Period, Tax	[3]													(5)	150	135
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax														$ 10	$ (298)	$ (243)

[1] Includes charges of $(360) million and $(1,109) million during the period September 1 - September 30, 2017 and the fourth quarter 2017, respectively, related to the amortization of inventory step-up as a result of the Merger and the acquisition of the H&N Business, which was included in cost of goods sold. See Note 3 for additional information.

[2] Cost of goods sold.

[3] Provision for income taxes from continuing operations.

[4] Sundry income - net.

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