Basis of Presentation and Summary of Significant Accounting Policies Divestiture (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture	$ 47	$ 0
Loss on divestiture	1	$ 0
Disposal Group, Including Discontinued Operation, Other Assets, Current	11		$ 89
Disposal Group, Including Discontinued Operation, Other Liabilities, Current	$ 4		39
Other Expense [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down			$ 34