Income Taxes, Unrecognized Tax Benefits Recognized in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Other long-term liabilities and Deferred tax liabilities	$ 721	$ 723
Uncertain tax position liabilities presented in our balance sheets	781	744
Income Taxes Payable [Member]
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Income taxes payable	42	0
Other Long-term Liabilities [Member]
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Other long-term liabilities and Deferred tax liabilities	721	723
Deferred Tax Liabilities[Member]
Amounts Recognized in Balance Sheets for Uncertain Tax Positions
Other long-term liabilities and Deferred tax liabilities	$ 18	$ 21