Postretirement Benefit Plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 18	$ 19	$ 22
Interest cost	38	35	42
Expected return on plan assets	(41)	(42)	(41)
Amortization of prior service cost (credit)	0	0	0
Recognized net actuarial loss	9	17	14
Net periodic benefit costs	24	29	37
Settlement losses	10	23	36
Total, including other postretirement losses	34	52	73
U.S. | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	5	5
Interest cost	14	15	17
Expected return on plan assets	(14)	(15)	(17)
Amortization of prior service cost (credit)	(1)	(3)	(4)
Recognized net actuarial loss	0	2	3
Net periodic benefit costs	2	4	4
Settlement losses	0	0	0
Total, including other postretirement losses	2	4	4
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	36	37
Interest cost	43	45	44
Expected return on plan assets	(86)	(67)	(62)
Amortization of prior service cost (credit)	1	(1)	(2)
Recognized net actuarial loss	29	20	28
Net periodic benefit costs	18	33	45
Settlement losses	3	3	2
Total, including other postretirement losses	$ 21	$ 36	$ 47