Pension Plans and Other Post Employment Benefit Plans Components of net periodic benefit cost (credit) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Successor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		$ 33		$ 67
Interest Cost		189		379
Expected return on plan assets		(301)		(604)
Amortization of unrecognized (gain) loss		(1)		(1)
Amortization of prior service benefit		0		0
Curtailment/settlement gain	[1]	(4)		(4)
Net periodic benefit (credit) cost		(84)		(163)
Successor [Member] | Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		2		4
Interest Cost		22		43
Amortization of unrecognized (gain) loss		0		0
Amortization of prior service benefit		0		0
Predecessor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost			$ 34		$ 67
Interest Cost			197		392
Expected return on plan assets			(309)		(617)
Amortization of unrecognized (gain) loss			189		379
Amortization of prior service benefit			(1)		(2)
Curtailment/settlement gain			0		0
Net periodic benefit (credit) cost			110		219
Predecessor [Member] | Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost			2		4
Interest Cost			23		45
Amortization of unrecognized (gain) loss			23		46
Amortization of prior service benefit			(18)		(35)
Discontinued Operations [Member] | Successor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (credit) cost		0		0
Discontinued Operations [Member] | Predecessor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (credit) cost			1		2
Continuing Operations [Member] | Successor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (credit) cost		(84)		(163)
Continuing Operations [Member] | Successor [Member] | Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (credit) cost		$ 24		$ 47
Continuing Operations [Member] | Predecessor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (credit) cost			109		217
Continuing Operations [Member] | Predecessor [Member] | Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit (credit) cost			$ 30		60
Principal U.S. Pension Plan [Member] | Predecessor [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer Contributions					$ 2,900

[1] 1. The 2018 impact relates to the curtailment and settlement of pension plans in the U.S. and Australia.