Pension and Other Postretirement Benefit Plans - Net Periodic Costs Recognized in Operating Profit and Interest and Sundry (Income) Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		99 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	$ 2	$ 2	$ (1)	$ 11	$ (89)
Operating profit | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	1	1	3	3
Interest and sundry (income) expense | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	1	1	(4)	8
United States Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	(2)	0	(3)	0
United States Pension Benefits | Operating profit
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	0	0	1	1
United States Pension Benefits | Interest and sundry (income) expense
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	(2)	0	(4)	(1)
Foreign Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	2	(2)	5	0
Foreign Pension Benefits | Operating profit
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	2	2	3	3
Foreign Pension Benefits | Interest and sundry (income) expense
Defined Benefit Plan Disclosure [Line Items]
Net periodic cost	$ 0	$ (4)	$ 2	$ (3)