Pension, Savings and Other Postretirement Benefit Plans - Defined Benefit Pension Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
U.S.
Defined Benefit Plan, Net Periodic Benefit Cost
Service cost — benefits earned during the period	$ 1	$ 1
Interest cost on projected benefit obligation	42	61
Expected return on plan assets	(64)	(75)
Amortization of net losses	27	28
Net periodic pension cost	6	15
Non-U.S.
Defined Benefit Plan, Net Periodic Benefit Cost
Service cost — benefits earned during the period	7	9
Interest cost on projected benefit obligation	20	29
Expected return on plan assets	(22)	(26)
Amortization of net losses	7	9
Net periodic pension cost	$ 12	$ 21