Postretirement Benefit Plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
U.S. defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 6	$ 16	$ 17
Interest cost	10	10	32	31
Expected return on plan assets	(10)	(12)	(31)	(36)
Recognized net actuarial loss	5	4	15	14
Amortization of prior service cost (credit)	0	0	0	0
Net periodic benefit costs	10	8	32	26
Settlement losses	4	7	17	19
Total	14	15	49	45
U.S. retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	4	4
Interest cost	5	5	15	15
Expected return on plan assets	(4)	(5)	(14)	(16)
Recognized net actuarial loss	2	2	5	6
Amortization of prior service cost (credit)	(1)	0	(3)	3
Net periodic benefit costs	3	3	7	12
Settlement losses	0	0	0	0
Total	3	3	7	12
Non-U.S. defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	9	25	26
Interest cost	14	13	40	40
Expected return on plan assets	(18)	(19)	(52)	(57)
Recognized net actuarial loss	6	6	19	18
Amortization of prior service cost (credit)	0	0	(1)	(1)
Net periodic benefit costs	11	9	31	26
Settlement losses	0	0	1	2
Total	$ 11	$ 9	$ 32	$ 28