Pension Plans and Other Post Employment Benefit Plans Change in Projected Benefit Obligations, Plan Assets and Funded Status (Details) - USD ($) $ in Millions		3 Months Ended		4 Months Ended	8 Months Ended		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Aug. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at end of the period		$ 389		$ 389
Successor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period	[1]			26,036
Service Cost				49
Interest Cost				247
Plan participants' contributions				6
Actuarial (gain) loss				(23)
Benefits Paid				(730)
Plan amendments				0
Net effects of acquisitions / divestitures / other				22
Effect of foreign exchange rates				(57)
Benefit obligation at end of the period		25,550		25,550	$ 26,036	[1]
Fair value of plan assets at beginning of period	[1]			20,395
Actual return on plan assets				549
Employer contributions				68
Plan participants' contributions				6
Benefits paid	[2]			(730)
Net effects of acquisitions / divestitures / other				29
Effect of foreign exchange rates				(33)
Fair value of plan assets at end of the period		20,284		20,284	20,395	[1]
Funded (unfunded) status of plan		(5,266)		(5,266)
Successor [Member] | Pension Plan | Principal U.S. Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Lump-Sum Payments		140
Successor [Member] | Pension Plan | U.S. Plans with Plan Assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		(3,628)		(3,628)
Successor [Member] | Pension Plan | Non-U.S. plans with plan assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		(447)		(447)
Successor [Member] | Pension Plan | All other plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan	[3],[4]	(1,191)		(1,191)
Successor [Member] | Pension Plan | Plans of Discontinued Operations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		0		0
Successor [Member] | Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period	[1]			2,772
Service Cost				3
Interest Cost				26
Plan participants' contributions				12
Actuarial (gain) loss				68
Benefits Paid				(71)
Plan amendments				0
Net effects of acquisitions / divestitures / other				0
Effect of foreign exchange rates				0
Benefit obligation at end of the period		2,810		2,810	2,772	[1]
Fair value of plan assets at beginning of period	[1]			0
Actual return on plan assets				0
Employer contributions				59
Plan participants' contributions				12
Benefits paid				(71)
Net effects of acquisitions / divestitures / other				0
Effect of foreign exchange rates				0
Fair value of plan assets at end of the period		0		0	0	[1]
Funded (unfunded) status of plan		(2,810)		(2,810)
Successor [Member] | Other Post Employment Benefits Plan | U.S. Plans with Plan Assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		0		0
Successor [Member] | Other Post Employment Benefits Plan | Non-U.S. plans with plan assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		0		0
Successor [Member] | Other Post Employment Benefits Plan | All other plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		(2,810)		(2,810)
Successor [Member] | Other Post Employment Benefits Plan | Plans of Discontinued Operations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		$ 0		0
Predecessor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period				24,766	24,831		$ 26,094
Service Cost					92		174		$ 232
Interest Cost					524		800		1,084
Plan participants' contributions					8		18
Actuarial (gain) loss					0		460
Benefits Paid					(1,118)		(2,374)
Plan amendments					0		0
Net effects of acquisitions / divestitures / other					0		7
Effect of foreign exchange rates					429		(348)
Benefit obligation at end of the period			$ 24,831		24,766		24,831		26,094
Fair value of plan assets at beginning of period				19,685	16,656		17,497
Actual return on plan assets					846		1,219
Employer contributions					3,024		535
Plan participants' contributions					8		18
Benefits paid					(1,118)		(2,374)	[2]
Net effects of acquisitions / divestitures / other					0		0
Effect of foreign exchange rates					269		(239)
Fair value of plan assets at end of the period			16,656		19,685		16,656		17,497
Funded (unfunded) status of plan			(8,175)		(5,081)		(8,175)
Predecessor [Member] | Pension Plan | Principal U.S. Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions					2,900		230
Lump-Sum Payments			550
Predecessor [Member] | Pension Plan | U.S. Plans with Plan Assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			(6,391)		(3,277)		(6,391)
Predecessor [Member] | Pension Plan | Non-U.S. plans with plan assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			(674)		(609)		(674)
Predecessor [Member] | Pension Plan | All other plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			(1,102)		(1,187)		(1,102)
Predecessor [Member] | Pension Plan | Plans of Discontinued Operations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			(8)		(8)		(8)
Predecessor [Member] | Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period				2,731	2,829		2,758
Service Cost					6		11		15
Interest Cost					60		87		112
Plan participants' contributions					26		36
Actuarial (gain) loss					0		153
Benefits Paid					(192)		(254)
Plan amendments					0		(28)
Net effects of acquisitions / divestitures / other					0		65
Effect of foreign exchange rates					2		1
Benefit obligation at end of the period			2,829		2,731		2,829		2,758
Fair value of plan assets at beginning of period				$ 0	0		0
Actual return on plan assets					0		0
Employer contributions					166		218
Plan participants' contributions					26		36
Benefits paid					(192)		(254)
Net effects of acquisitions / divestitures / other					0		0
Effect of foreign exchange rates					0		0
Fair value of plan assets at end of the period			0		0		0		$ 0
Funded (unfunded) status of plan			(2,829)		(2,731)		(2,829)
Predecessor [Member] | Other Post Employment Benefits Plan | U.S. Plans with Plan Assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			0		0		0
Predecessor [Member] | Other Post Employment Benefits Plan | Non-U.S. plans with plan assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			0		0		0
Predecessor [Member] | Other Post Employment Benefits Plan | All other plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			(2,829)		(2,731)		(2,829)
Predecessor [Member] | Other Post Employment Benefits Plan | Plans of Discontinued Operations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan			$ 0		$ 0		$ 0

[1] The benefit obligation and the fair value of plan assets at the beginning of the period September 1 through December 31, 2017, reflects the remeasurement of the plans at the Merger Effectiveness Time.

[2] In the fourth quarter of 2016, about $550 million of lump-sum payments were made from the principal U.S. pension plan trust fund to a group of separated, vested plan participants who were extended a limited-time opportunity and voluntarily elected to receive their pension benefits in a single lump-sum payment. In the fourth quarter of 2017, about $140 million of lump-sum payments were made from the principal U.S. pension plan trust fund under a similar program.

[3] As of December 31, 2017, $389 million of the benefit obligations are supported by funding under the Trust agreement, defined in the "Trust Assets" section below.

[4] Includes pension plans maintained around the world where funding is not customary.