Income Taxes (Details 6) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Effective Income Tax Reconciliation, change in enacted tax rate due to 2017 Tax Act, amount	$ 5	$ 285
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%	35.00%
Impacts related to the 2017 Tax Act, Percent	0.10%	6.80%
Change in Deferred Tax Assets due to 2017 Tax Act	$ 12	$ (358)
Change in Other Current Liabilities due to 2017 Tax Act	17	(73)
Reduction in Taxes [Member]
Income Tax Contingency [Line Items]
Effective Income Tax Reconciliation, change in enacted tax rate due to 2017 Tax Act, amount	$ 0	$ 265
Impacts related to the 2017 Tax Act, Percent	0.00%	6.30%
Change in Deferred Tax Assets due to 2017 Tax Act	$ 0	$ (265)
Change in Other Current Liabilities due to 2017 Tax Act	0	0
Transition tax on Foreign Earnings [Member]
Income Tax Contingency [Line Items]
Effective Income Tax Reconciliation, change in enacted tax rate due to 2017 Tax Act, amount	$ 5	$ 13
Impacts related to the 2017 Tax Act, Percent	0.10%	0.30%
Change in Deferred Tax Assets due to 2017 Tax Act	$ (5)	$ (13)
Change in Other Current Liabilities due to 2017 Tax Act	0	0
Accelerated Depreciation [Member]
Income Tax Contingency [Line Items]
Effective Income Tax Reconciliation, change in enacted tax rate due to 2017 Tax Act, amount	$ 0	$ 5
Impacts related to the 2017 Tax Act, Percent	0.00%	0.10%
Change in Deferred Tax Assets due to 2017 Tax Act	$ 17	$ (80)
Change in Other Current Liabilities due to 2017 Tax Act	17	(75)
2017 Tax Act, Other [Domain]
Income Tax Contingency [Line Items]
Effective Income Tax Reconciliation, change in enacted tax rate due to 2017 Tax Act, amount	$ 0	$ 2
Impacts related to the 2017 Tax Act, Percent	0.00%	0.10%
Change in Deferred Tax Assets due to 2017 Tax Act	$ 0	$ 0
Change in Other Current Liabilities due to 2017 Tax Act	$ 0	$ 2