Earnings Per Share 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, 2017	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Net income	$ 644	$ 440
Weighted Average Number of Shares Outstanding, Basic	309	301
Dilutive potential common shares related to stock award plans and from assumed exercise of stock options	4	4
Weighted Average Number of Shares Outstanding, Diluted	313	315
Basic	$ 2.08	$ 1.46
Diluted	$ 2.06	$ 1.40
Convertible Debt
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	0	2
Warrants
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	0	8