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, 2019	Jun. 30, 2018
Earnings Per Share Reconciliation [Abstract]
Net income (loss)	$ 1,421	$ 293
Weighted Average Number of Shares Outstanding, Basic	297	306
Dilutive potential common shares related to stock award plans and from assumed exercise of stock options	2	4
Weighted Average Number of Shares Outstanding, Diluted	299	310
Earnings Per Share, Basic	$ 4.78	$ 0.96
Earnings Per Share, Diluted	$ 4.75	$ 0.95