Benefit Obligations (Schedule of Percentage of US and International Projected Benefit Obligation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	$ 233	$ 232
Percentage of projected benefit obligation	100.00%	100.00%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	$ 4	$ 4
Percentage of projected benefit obligation	100.00%	100.00%
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of projected benefit obligation	83.00%	85.00%
Domestic Plan [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of projected benefit obligation	54.00%	57.00%
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of projected benefit obligation	17.00%	15.00%
Foreign Plan [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of projected benefit obligation	46.00%	43.00%