Pensions, Other Post-employment Benefits and Employee Benefit Plans Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits
Net Periodic Benefit Cost [Line Items]
Service cost	$ 19	$ 16	$ 16
Interest cost	66	76	69
Expected return on plan assets	(71)	(74)	(70)
Amortization of actuarial losses	26	10	27
Amortization of prior service credit	0	0	0
Settlement (gain) loss	0	(2)	1
Curtailment gain	(2)	0	0
Net periodic benefit cost	38	26	43
Other Post-Employment Benefits
Net Periodic Benefit Cost [Line Items]
Service cost	0	0	0
Interest cost	13	15	11
Expected return on plan assets	0	0	0
Amortization of actuarial losses	5	3	6
Amortization of prior service credit	(4)	(5)	(9)
Settlement (gain) loss	0	0	0
Curtailment gain	0	0	(40)
Net periodic benefit cost	$ 14	$ 13	$ (32)