New Accounting Pronouncements to be Adopted (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	May 01, 2018	May 01, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 10
Accounting Standards Update 2014-09 [Member] | Scenario, Forecast [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ (30)
Accounting Standards Update 2016-15 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Cash Provided by (Used in) Operating Activities	$ 21	$ 17
Accounting Standards Update 2016-16 [Member] | Scenario, Forecast [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ 27
Accounting Standards Update 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Operating Results	$ 9	$ 21