Commitments and Contingent Liabilities Other PFOA Matters / Fayetteville (Details)	9 Months Ended
	Sep. 30, 2020 lawsuits
Firefighting Foam [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	690
Personal injury cases [Member] | Firefighting Foam [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	630
NEW YORK | PFOA Matters: Drinking Water Actions [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	50
NEW JERSEY | PFOA Matters: Drinking Water Actions [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	2
NEW JERSEY | Natural Resources Damages [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	4
OHIO | PFOA Matters: Drinking Water Actions [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	3
NORTH CAROLINA | PFOA Matters: Drinking Water Actions [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Property Owners	200
Loss Contingency, Number of Additional Plaintiffs	100
Alabama Water Utility [Member] | Natural Resources Damages [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	1