Commitments and Contingencies Environmental (Details) - Environmental Issue $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($) sites	Sep. 30, 2019 USD ($)
Loss Contingencies [Line Items]
Number of alleged environmental contamination sites | sites	200
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 282	$ 298
Accruals / changes in estimates	2	0
Payments	(15)	(16)
Ending balance	269	282
Current portion of ending balance	35	$ 40
Minimum
Loss Contingencies [Line Items]
Future costs to settle claims and associated liability	220
Maximum
Loss Contingencies [Line Items]
Future costs to settle claims and associated liability	$ 360