Earnings Per Share (Computation Of Basic Earnings And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share Reconciliation [Abstract]
Net income (loss)	$ 294	$ 185	$ 498	$ 550
Weighted Average Number of Shares Outstanding, Basic	285	289	285	289
Dilutive potential common shares related to stock award plans and from assumed exercise of stock options	2	4	3	3
Weighted Average Number of Shares Outstanding, Diluted	287	293	288	292
Earnings Per Share, Basic	$ 1.03	$ 0.64	$ 1.75	$ 1.90
Earnings Per Share, Diluted	$ 1.02	$ 0.63	$ 1.73	$ 1.88