Segment Information (Long-Lived Assets By Geographic Area) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Long-Lived Assets [Line Items]
Long-lived Assets	$ 1,225	$ 1,251
North America [Member]
Long-Lived Assets [Line Items]
Long-lived Assets	389	399
Europe [Member]
Long-Lived Assets [Line Items]
Long-lived Assets	84	88
Rest of World [Member]
Long-Lived Assets [Line Items]
Long-lived Assets	$ 752	$ 764