Income Taxes Deferred Tax Assets, Balance Sheet Location (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Asset, Balance Sheet Location [Line Items]
Deferred Tax Assets, Net	$ 125
Deferred Tax Liabilities, Net		$ (14)
Long-term assets
Deferred Tax Asset, Balance Sheet Location [Line Items]
Deferred Tax Assets, Net	283	238
Long-term liabilities
Deferred Tax Asset, Balance Sheet Location [Line Items]
Deferred Tax Liabilities, Net	$ (158)	$ (252)