Pension and Other Postretirement Benefits - About our Plans (Details) - United States [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan cost	$ (3)	$ (4)	$ 159	$ (8)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan cost	$ 2	$ 1	$ 3	$ 3