Pension Plans, Postretirement and Other Employee Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
US | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	$ 0	$ 0
Interest cost	3	3
Expected return on plan assets	(4)	(4)
Net amortization:
Actuarial loss	1	1
Net pension and postretirement costs	0	0
US | Postretirement
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	0	0
Interest cost	2	1
Expected return on plan assets	0	0
Net amortization:
Actuarial loss	1	1
Net pension and postretirement costs	3	2
Foreign | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	3	2
Interest cost	3	3
Expected return on plan assets	(5)	(4)
Net amortization:
Actuarial loss	2	2
Net pension and postretirement costs	$ 3	$ 3