Segment Information (Long-Lived Assets By Geographic Area) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Long-Lived Assets [Line Items]
Long-lived Assets	$ 1,322	$ 1,309
North America [Member]
Long-Lived Assets [Line Items]
Long-lived Assets	446	445
Europe [Member]
Long-Lived Assets [Line Items]
Long-lived Assets	100	104
Rest of World [Member]
Long-Lived Assets [Line Items]
Long-lived Assets	$ 776	$ 760