Stockholders' Equity Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Oct. 31, 2021	Jul. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ (422)			$ (422)
Net other comprehensive income (loss)	$ 2	8	$ 15	$ 24	10	$ 39
Ending balance	(412)				(412)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(179)			(179)
Net other comprehensive income (loss)	(12)		4		(22)	66
Ending balance	(201)				(201)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(16)			(16)
Net other comprehensive income (loss)	10		6		24	(39)
Ending balance	8				8
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(227)			(227)
Net other comprehensive income (loss)	4		5		8	$ 12
Ending balance	(219)				$ (219)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net other comprehensive income (loss)	$ 2	$ 8	$ 15	$ 24