Commitments and Contingent Liabilities Other PFOA Matters / Fayetteville (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($) lawsuits	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Guarantee Obligations | $	$ 108	$ 94	$ 90
Factoring Agreement [Member]
Loss Contingencies [Line Items]
Guarantee Obligations | $	$ 23	$ 17	$ 17
Firefighting Foam [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	985
Personal injury cases [Member] | Firefighting Foam [Member]
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	910
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	100
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