Pension, Savings and Other Postretirement Benefit Plans - Defined Benefit Pension Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
U.S.
Defined Benefit Plan, Net Periodic Benefit Cost
Service cost	$ 1	$ 1
Interest cost	44	40
Expected return on plan assets	(56)	(55)
Amortization of net losses	28	28
Net periodic pension cost	17	14
Non-U.S.
Defined Benefit Plan, Net Periodic Benefit Cost
Service cost	7	7
Interest cost	18	18
Expected return on plan assets	(15)	(18)
Amortization of net losses	7	7
Net periodic pension cost	17	14
Net curtailments/settlements/termination benefits	1	0
Total defined benefit pension cost	$ 18	$ 14