Description Of Business And Basis of Presentation (Impact of Recently Adopted Accounting Standards) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	$ 242	$ 193
Operating Lease, Liability, Current	76	69
Operating Lease, Liability, Noncurrent	202	155
Consolidated Balance Sheet Statements, Captions [Line Items]
Other current assets	326	321
Other assets	362	305
Accrued and other current liabilities	1,341	1,052
Other liabilities	$ 250	$ 216