Postretirement Benefit Plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
U.S. defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6	$ 6	$ 11	$ 11
Interest cost	11	11	21	22
Expected return on plan assets	(10)	(11)	(20)	(21)
Recognized net actuarial loss	3	5	7	10
Amortization of prior service credit	0	0	0	0
Net periodic benefit costs	10	11	19	22
Settlement losses	4	7	10	13
Total, including other postretirement losses	14	18	29	35
U.S. retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	2	3
Interest cost	5	5	9	10
Expected return on plan assets	(5)	(5)	(9)	(10)
Recognized net actuarial loss	1	1	2	3
Amortization of prior service credit	(1)	(1)	(2)	(2)
Net periodic benefit costs	1	2	2	4
Settlement losses	0	0	0	0
Total, including other postretirement losses	1	2	2	4
Non-U.S. defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	8	18	16
Interest cost	11	13	22	26
Expected return on plan assets	(15)	(17)	(31)	(34)
Recognized net actuarial loss	7	7	14	13
Amortization of prior service credit	(1)	(1)	(1)	(1)
Net periodic benefit costs	11	10	22	20
Settlement losses	1	0	1	1
Total, including other postretirement losses	$ 12	$ 10	$ 23	$ 21