Pension and Other Postretirement Benefit Plans (Estimated Pre-Tax Amounts That Will Be Amortized from Accumulated OCI) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amortization of prior service credit (in years)	21 years
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss	$ 1
Prior service (credit)	(9)
Total	(8)
United States Pension Benefits | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss	47
Prior service (credit)	(2)
Total	45
Foreign Pension Benefits | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss	8
Prior service (credit)	0
Total	$ 8