v3.19.1
Income Taxes (Income Tax Expense (Benefit)) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Income Tax [Line Items]      
Valuation Allowance, Deferred Tax Asset, Change in Amount $ 168 $ 413 $ 56
U.S. 47 (358) 116
International 27 27 24
Total $ 74 $ (331) $ 140