Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 30, 2013		Apr. 30, 2012		Apr. 30, 2011
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 9		$ 18		$ 16
Additions Charged to Costs and Expenses	2		0		1
Additions Charged to Other Accounts	0		0		1	[1]
Deductions	2	[2]	9	[2]	0
Balance at End of Period	9		9		18
Restructuring Charges [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period					2
Additions Charged to Costs and Expenses					0
Additions Charged to Other Accounts					0
Deductions					2	[3]
Balance at End of Period					$ 0

[1] Foreign currency translation adjustment charged to accumulated other comprehensive income

[2] Doubtful accounts written off, net of recoveries.

[3] Special termination benefit payments and amounts reclassified to accrued postretirement benefits.