Income Taxes (Deferred Tax Liabilities Not Recognized) (Details) - USD ($) $ in Millions	Apr. 30, 2019	Apr. 30, 2018
Income Tax Disclosure [Abstract]
Undistributed earnings of foreign subsidiaries	$ 1,266	$ 1,270

Amount of undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.

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