Pension and Other Retiree Benefits (Weighted Average Assumptions Used in Calculating Benefit Obligation) (Details)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension | U.S.
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.70%	4.30%	4.60%
Pension | International
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.30%	2.70%	3.70%
Rate of compensation increase	2.80%	3.10%	3.00%
Post-retirement
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.20%	3.40%	3.90%