Segment Information (Long-Lived Assets By Geographic Area) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 491	$ 449
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	397	375
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 94	$ 74