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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 01, 2019	May 31, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan						$ 5,800
Restricted Cash						$ 319
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate							3.64%	4.23%
Defined Benefit Plan Remeasurement Impact Underfunded Status					$ 114
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		$ 8	$ 12	$ 13	32
Interest Cost		140	199	281	407
Expected return on plan assets		(249)	(282)	(500)	(586)
Amortization of unrecognized loss (gain)		1	1	2	2
Amortization of Prior Service Benefit		(1)	0	(1)	0
Settlement/Curtailment Loss (Gain)		1	(1)	3	(1)
Defined Benefit Plan, Net Periodic Benefit (Credit) Cost		(100)	(71)	(202)	(146)
Other Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		0	1	1	3
Interest Cost		17	22	33	45
Amortization of unrecognized loss (gain)		0	(1)	0	(1)
Discontinued Operations [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Credit) Cost	[1]	0	(9)	0	(17)
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			(16)		(37)
Continuing Operations [Member] | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Credit) Cost		(100)	(62)	(202)	(129)
Continuing Operations [Member] | Other Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Credit) Cost		$ 17	$ 22	$ 34	$ 47

[1] Includes non-service related components of net periodic benefit credit of $(16) million and $(37) million for the three and six months ended June 30, 2019, respectively.