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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share Reconciliation [Abstract]
Net income (loss)	$ 854	$ 255	$ 2,275	$ 548
Weighted Average Number of Shares Outstanding, Basic	295	305	296	305
Dilutive potential common shares related to stock award plans and from assumed exercise of stock options	1	2	1	4
Weighted Average Number of Shares Outstanding, Diluted	296	307	297	309
Earnings Per Share, Basic	$ 2.89	$ 0.84	$ 7.69	$ 1.80
Earnings Per Share, Diluted	$ 2.89	$ 0.83	$ 7.66	$ 1.77