Debt Short-term Borrowings (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Jul. 31, 2021	Apr. 30, 2021
Short-term Debt [Abstract]
Short-term borrowings	$ 155	$ 205
Commercial Paper	$ 135	$ 195
Commercial Paper, Weighted Average Interest Rate, at Point in Time	0.17%	0.16%
Commercial Paper Borrowings, Average Remaining Maturity	16 days	24 days

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant