Pension Plans, Postretirement and Other Employee Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
US | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	$ 0	$ 0	$ 0	$ 0
Interest cost	2	2	5	5
Expected return on plan assets	(3)	(3)	(7)	(7)
Settlement loss		6	0	6
Net amortization:
Actuarial loss	1	2	2	3
Prior service credit	0	0	0	0
Net pension and postretirement costs	0	1	0	7
US | Postretirement
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	0	0	0	0
Interest cost	1	2	3	3
Expected return on plan assets	0	0	0	0
Settlement loss			0	0
Net amortization:
Actuarial loss	3	2	4	3
Prior service credit	(1)	(1)	(1)	(1)
Net pension and postretirement costs	3	3	6	5
Foreign | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	2	2	5	4
Interest cost	3	3	6	6
Expected return on plan assets	(5)	(11)	(10)	(15)
Settlement loss			0	0
Net amortization:
Actuarial loss	2	3	4	5
Prior service credit	0	0	0	0
Net pension and postretirement costs	$ 2	$ (3)	$ 5	$ 0