Commitments and Contingent Liabilities Environmental (Details) $ in Millions	Mar. 31, 2018 USD ($)
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	$ 430
Accrual for Environmental Loss Contingencies, Potential Exposure in Excess of Accrual	885
Superfund Sites [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	61
Chemours [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	242
Accrual for Environmental Loss Contingencies, Potential Exposure in Excess of Accrual	430
Indemnification Agreement [Member] | Chemours [Member]
Loss Contingencies [Line Items]
Indemnification Assets	242
Indemnification Agreement [Member] | Chemours [Member] | Superfund Sites [Member]
Loss Contingencies [Line Items]
Indemnification Assets	$ 42