Income Taxes, Classification of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Non-current deferred tax assets	$ 5		$ 3
Non-current deferred tax liabilities	(196)	$ (162)	(158)
Total deferred tax liabilities, net of valuation allowance	$ (191)		$ (155)