Income Taxes, Unrecognized Tax Benefits Recognized in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Other long-term liabilities and Deferred tax liabilities	$ (723)	$ (465)
Uncertain tax position liabilities presented in our balance sheets	(744)	(498)
Income Taxes Payable [Member]
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Income taxes payable	0	(7)
Other Noncurrent Liabilities [Member]
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Other long-term liabilities and Deferred tax liabilities	(723)	(465)
Deferred Income Taxes [Member]
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Other long-term liabilities and Deferred tax liabilities	$ (21)	$ (26)