Pension Benefits Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Liability, Other Retirement Benefits	$ 1		$ 1		$ 1
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	11	$ 13	22	$ 24
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	13	12	27	23
Service cost	$ 9	$ 9	$ 19	$ 17