Employee Benefit Plans (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 3	$ 3
Expected return on plan assets	(1)	(2)
Amortization of prior service credit	(1)	0
Amortization of net loss	0	1
Net periodic cost	1	$ 2
Expected contribution to postretirement benefit plan in current year	7
Total contribution to the plan during the period	$ 2