Income Taxes Textuals (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Taxes (Textuals) [Line Items]
U.S. Tax Act Discrete Tax (Benefit) charge				$ 24
Effective tax rate	13.80%	5.40%	13.70%	(8.00%)
Reduction in Effective Tax Rate				11.90%
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction			2015
Internal Revenue Service (IRS) [Member] | Earliest Year [Member]
Income Tax Contingency [Line Items]
Tax Audit Settlement Years					2008
Internal Revenue Service (IRS) [Member] | Latest Year [Member]
Income Tax Contingency [Line Items]
Tax Audit Settlement Years					2014