Offsetting Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Jan. 31, 2022	Apr. 30, 2021
Offsetting Assets and Liabilities [Line Items]
Gross Amount of Derivative Assets	$ 34	$ 10
Gross Amount of Derivative Liabilities Offset Against Derivative Assets in Balance Sheet	(4)	(7)
Net Amount of Derivative Assets Presented in Balance Sheet	30	3
Gross Amount of Derivative Liabilities Not Offset Against Derivative Assets in Balance Sheet	0	(1)
Net Amount of Derivative Assets	30	2
Gross Amount of Derivative Liabilities	(6)	(38)
Gross Amount of Derivative Assets Offset Against Derivative Liabilities in Balance Sheet	4	7
Net Amount of Derivative Liabilities Presented in Balance Sheet	2	31
Gross Amount of Derivative Assets Not Offset Against Derivative Liabilities in Balance Sheet	0	1
Net Amount of Derivative Liabilities	$ 2	$ 30