Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Employee Severance
Restructuring Cost and Reserve [Line Items]
Write-down of a long-term asset			$ 0
Cost Management Initiatives
Restructuring Cost and Reserve [Line Items]
Anticipated restructuring costs	$ 125		125
Cost incurred to date	99		99
Restructuring charges	24		$ 45
Write-down of a long-term asset	$ 21
Cost Management Initiatives | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 19		$ 20