Pension and Postretirement Benefit Plans - 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
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	$ 258		$ 258
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Interest cost	17	$ 10	26	$ 21
Expected return on plan assets	(20)	(17)	(32)	(35)
Service cost
Settlement charge	258		258
Amortization of net actuarial loss	10	7	15	14
Net periodic benefit cost	265	0	267	0
Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2	2	4	3
Expected return on plan assets	(1)		(2)	(1)
Service cost	2	2	4	4
Settlement charge
Amortization of net actuarial loss	1	1	3	3
Net periodic benefit cost	4	5	9	9
Other Postretirement Benefits Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	0	1	1	2
Expected return on plan assets
Service cost
Settlement charge
Amortization of net actuarial loss
Net periodic benefit cost	$ 0	$ 1	$ 1	$ 2