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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
US | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 1	$ 0
Interest cost	14	2	27	5
Expected return on plan assets	(17)	(3)	(34)	(7)
Net amortization:
Actuarial loss	1	1	2	2
Prior service cost (credit)	0	0	0	0
Net pension and postretirement costs (credits)	(2)	0	(4)	0
US | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	4	1	7	3
Expected return on plan assets	0	0	0	0
Net amortization:
Actuarial loss	1	3	2	4
Prior service cost (credit)	(2)	(1)	(4)	(1)
Net pension and postretirement costs (credits)	3	3	5	6
Non-U.S. | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	2	12	5
Interest cost	5	3	12	6
Expected return on plan assets	(4)	(5)	(9)	(10)
Net amortization:
Actuarial loss	2	2	3	4
Prior service cost (credit)	0	0	0	0
Net pension and postretirement costs (credits)	$ 9	$ 2	$ 18	$ 5