Income Taxes (Textual) (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2014	Apr. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Foreign Earnings Repatriated	$ 120
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	30.40%	35.00%
Income Tax Benefit from Reduction in Federal Statutory Income Tax Rate	$ 0
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Amount	12
Tax Cuts and Jobs Act, Incomplete Accounting, Provisional Income Tax Expense (Benefit)		$ 43
Tax Cuts and Jobs Act, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense		91
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)		(48)
Tax Cuts and Jobs Act, Measurement Period Adjustment, Income Tax Expense (Benefit)	4
Deferred Income, Tax Benefit of Intercompany Transfer of Assets, Before Amortization				$ 95
Deferred Income, Tax Benefit of Intercompany Transfer of Assets, Cumulative Amortization		68
Deferred Tax Assets, Valuation Allowance	25	29
Gross unrecognized tax benefits	11	11	$ 9		$ 9
Reduction in effective income tax rate if recognized	9
Estimated increase in unrecognized tax benefits in next 12 months as a result of net tax positions taken	$ 0
Deferred Income, Tax Benefit of Intercompany Transfer of Assets, Net of Amortization		$ 27