Commitments and Contingencies (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Leases, Operating
Operating leases, rent expense	$ 75	$ 79	$ 83
Sublease rental income received	4	$ 4	$ 4
Operating leases:
2016	56
2017	50
2018	45
2019	37
2020	32
2021 and thereafter	52
Total future minimum payments	272
Minimum sublease rentals due in the future under non-cancelable subleases	30
Purchase Obligations
Total purchase commitments	132
2016	73
2017 through 2018	53
2019 through 2020	6
2021 and thereafter	$ 0