Retirement Benefits (Schedule of Estimated Amounts That Will Be Amortized from Accumulated Other Comprehensive in the Next Fiscal Year) (Details) $ in Millions	Dec. 31, 2018 USD ($)
United States | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 44
United States | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	1
Foreign Plan | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service credit	0
Net actuarial loss	59
Projected cost (credit)	59
Foreign Plan | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service credit	(2)
Net actuarial loss	0
Projected cost (credit)	$ (2)