Pension and Other Postretirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	1	1	2	2
Recognized prior service credit	(10)	(10)	(19)	(20)
Recognized net loss	1	1	2	2
Net periodic cost (benefit)	(8)	(8)	(15)	(16)
Pension Benefits - U.S. Plans | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	4	9	7
Interest cost	11	13	23	25
Expected return on plan assets	(21)	(21)	(42)	(41)
Recognized net loss	12	13	24	26
Net periodic cost (benefit)	7	9	14	17
Pension Benefits - Non-U.S. Plans | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	6	14	12
Interest cost	20	19	39	38
Expected return on plan assets	(40)	(36)	(80)	(71)
Recognized prior service credit	(3)	(3)	(6)	(6)
Recognized net loss	11	11	22	21
Net periodic cost (benefit)	$ (5)	$ (3)	$ (11)	$ (6)