Restructuring Costs (Details) $ in Millions	1 Months Ended	12 Months Ended			24 Months Ended	52 Months Ended
	Mar. 31, 2017	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)
Restructuring Cost [Abstract]
Restructuring costs		$ 236	$ 386	$ 1,256
Employee separation costs		48	112
Employee Separation Activity
Liability balance at beginning of period		85	249
Employee separation costs		48	112
Reduction in liability (payments and other adjustments)		85	276
Liability balance at end of period		48	85	249	$ 85	$ 48
Other restructuring costs
Restructuring Cost [Abstract]
Restructuring costs		122	182	173
Other operating income (expense) | Employee separation
Restructuring Cost [Abstract]
Restructuring costs		48	112	525
Other operating income (expense) | Contract termination
Restructuring Cost [Abstract]
Restructuring costs		1	7	183
Other operating income (expense) | Long-lived asset impairments
Restructuring Cost [Abstract]
Restructuring costs		65	93	346
Other operating income (expense) | Defined benefit retirement plan curtailment losses
Restructuring Cost [Abstract]
Restructuring costs		0	(8)	29
Gosselies closure announcement
Restructuring Cost [Abstract]
Restructuring and Related Cost, Number of Positions Eliminated	2,000
Restructuring costs					$ 647
September 2015 announcement
Restructuring Cost [Abstract]
Restructuring costs		$ 43	$ 121	$ 817		$ 1,831