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
	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share Reconciliation [Abstract]
Net income (loss)	$ 365	$ 1,421
Weighted Average Number of Shares Outstanding, Basic	288	297
Dilutive potential common shares related to stock award plans and from assumed exercise of stock options	4	2
Weighted Average Number of Shares Outstanding, Diluted	292	299
Earnings Per Share, Basic	$ 1.27	$ 4.78
Earnings Per Share, Diluted	$ 1.25	$ 4.75