Employee Benefit Plan - Net Benefit Plan Expense (Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment gain		$ 8
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 8	18	$ 10
Interest cost	15	20	17
Expected return on plan assets	(23)	(27)	(21)
Amortization of prior service credits	(2)	(2)	(2)
Amortization of losses (gains)	9	9	8
Curtailment gain	0	(12)	0
Settlement loss	1	4	0
Total net benefit plan expense (income)	8	10	12
U. S. Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0	0
Interest cost	0	0	0
Expected return on plan assets	0	0	0
Amortization of prior service credits	(1)	(1)	(1)
Amortization of losses (gains)	(1)	(1)	(1)
Curtailment gain	0	0	0
Settlement loss	0	0	0
Total net benefit plan expense (income)	$ (2)	$ (2)	$ (2)