Quaterly Financial Data Quarterly Financial Data (Parentheticals) (Details) - USD ($) $ in Millions	3 Months Ended								4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2019		Dec. 31, 2018
Effect of Fourth Quarter Events [Line Items]
(Loss) Gain on sale or disposition of assets							$ 24
Loss on Extinguishment of Debt			$ (13)		$ (81)				$ 0	$ 0	$ (13)		$ (81)
Net exchange losses									(23)	(364)	(99)	[1],[2]	(127)	[1],[2],[3],[4]
Hedging Program [Member]
Effect of Fourth Quarter Events [Line Items]
Net exchange losses									91	$ (431)	(58)		94	[4]
Argentine peso devaluation [Member] | Hedging Program [Member]
Effect of Fourth Quarter Events [Line Items]
Net exchange losses		$ (33)									(51)		(68)
Tax Reform Foreign Currency Exchange Impact [Member] | Hedging Program [Member]
Effect of Fourth Quarter Events [Line Items]
Net exchange losses								$ (50)					(50)
Swiss Tax Reform [Member]
Effect of Fourth Quarter Events [Line Items]
Other Tax Benefit (Expense)		38
Brazil Valuation Allowance [Member]
Effect of Fourth Quarter Events [Line Items]
Other Tax Benefit (Expense)						$ (75)
Internal Entity Restructuring [Member]
Effect of Fourth Quarter Events [Line Items]
Other Tax Benefit (Expense)						(25)
Pension Resize [Member]
Effect of Fourth Quarter Events [Line Items]
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Benefit						114
Merger with Dow [Member]
Effect of Fourth Quarter Events [Line Items]
Business Combination, Fair Value Step-Up Of Acquired Inventory, Amount recognized in Cost of Goods sold		$ (15)	$ (52)	$ (205)	(130)	(109)	(676)	(639)	$ 425		272		$ 1,554
Sale of JV [Member]
Effect of Fourth Quarter Events [Line Items]
(Loss) Gain on sale or disposition of assets				$ (24)
Swiss VA [Member]
Effect of Fourth Quarter Events [Line Items]
Other Tax Benefit (Expense)	$ 34										$ 34
Tax charge (benefit) related to The Act [Member]
Effect of Fourth Quarter Events [Line Items]
Other Tax Benefit (Expense)					$ (274)	$ 16	$ (7)	$ (64)

[1] Includes a net $(51) million and $(68) million pre-tax exchange loss associated with the devaluation of the Argentine peso for the year ended December 31, 2019 and December 31, 2018, respectively.

[2] Includes a net $(51) million and $(68) million pre-tax exchange loss associated with the devaluation of the Argentine peso for the year ended December 31, 2019 and December 31, 2018, respectively.

[3] Includes a $(50) million foreign exchange loss for the year ended December 31, 2018 related to adjustments to foreign currency exchange contracts as a result of U.S. tax reform, which is included within significant items.

[4] Includes a $(50) million foreign exchange loss for the year ended December 31, 2018 related to adjustments to foreign currency exchange contracts as a result of U.S. tax reform.