Commitments and Contingencies (Guarantees - Demerger and Divesture Obligations Narrative) (Details) € in Millions, $ in Millions	239 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 EUR (€)
Indemnification Agreements Hoechst [Member]
Loss Contingencies [Line Items]
Number of divestiture agreements	19	19
Indemnification amount | €		€ 250
Indemnification ceiling amount | €		€ 750
Indemnification percentage exceeding ceiling amount	33.33%	33.33%
Loss contingency accrual, carrying value, payments | $	$ 91
Indemnification percentage, other	33.33%	33.33%
Divestiture Agreements [Member]
Loss Contingencies [Line Items]
Guarantor obligations, maximum exposure | $	$ 116