Common Stock (Details) - shares		12 Months Ended
	May 24, 2017	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Class of Stock [Line Items]
Treasury Stock, Shares, Retired		67,000,000
Common stock, Class A, voting [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized		170,000,000	170,000,000	85,000,000
Treasury Stock, Shares, Retired		0
Common Stock, Class B, nonvoting [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized		400,000,000	400,000,000
Treasury Stock, Shares, Retired	67,000,000	67,000,000