Income Taxes (Operating Loss Carryforwards) (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014 Other Countries [Member]	Apr. 30, 2014 Brazil [Member]	Apr. 30, 2014 UK Non Trading Loss [Member]	Apr. 30, 2014 Not Subject to Expiration [Member] Net Operating Loss Carryforward [Member] Foreign Tax Authority [Member] Brazil [Member]	Apr. 30, 2014 Not Subject to Expiration [Member] Non-Trading Loss Carryforward [Member] Foreign Tax Authority [Member] UNITED KINGDOM	Apr. 30, 2014 Subject to Expiration [Member] Net Operating Loss Carryforward [Member] Foreign Tax Authority [Member] MEXICO	Apr. 30, 2014 Subject to Expiration [Member] Net Operating Loss Carryforward [Member] Foreign Tax Authority [Member] Other Countries [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 34	$ 25
Net operating losses in Brazil, valuation allowance			7	19
Valuation Allowance, Deferred Tax Asset, Change in Amount			3	6
Non-trading loss carryforward, valuation allowance					8
Non-trading loss carryforward							0
Net operating losses						$ 0		$ 0	$ 0