Commitments and Contingencies Environmental (Details) - Environmental Issue [Member] $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($) sites	Sep. 30, 2018 USD ($)
Loss Contingencies [Line Items]
Number of alleged environmental contamination sites (in sites) | sites	200
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 298	$ 317
Accruals / changes in estimates	0	(5)
Payments	(16)	(13)
Ending balance	282	299
Current portion of ending balance	40	$ 35
Minimum [Member]
Loss Contingencies [Line Items]
Future costs to settle claims and associated liability	230
Maximum [Member]
Loss Contingencies [Line Items]
Future costs to settle claims and associated liability	$ 380