Fair Value Measurements (Details) (Recurring [Member], USD $) In Millions, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2012
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term borrowings	$ 3	$ 4
Current portion of long-term debt	2	3
Long-term debt	1,011	534
Currency derivatives [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Derivative assets	5	1
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities	4	7
Interest rate swaps [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Interest rate swaps		2
Commodity derivatives [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities		1
Level 1 [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term borrowings	0	0
Current portion of long-term debt	0	0
Long-term debt	0	0
Level 1 [Member] | Currency derivatives [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Derivative assets	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities	0	0
Level 1 [Member] | Interest rate swaps [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Interest rate swaps		0
Level 1 [Member] | Commodity derivatives [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities		1
Level 2 [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term borrowings	3	4
Current portion of long-term debt	2	3
Long-term debt	1,011	534
Level 2 [Member] | Currency derivatives [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Derivative assets	5	1
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities	4	7
Level 2 [Member] | Interest rate swaps [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Interest rate swaps		2
Level 2 [Member] | Commodity derivatives [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities		0
Level 3 [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term borrowings	0	0
Current portion of long-term debt	0	0
Long-term debt	0	0
Level 3 [Member] | Currency derivatives [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Derivative assets	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities	0	0
Level 3 [Member] | Interest rate swaps [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Interest rate swaps		0
Level 3 [Member] | Commodity derivatives [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative liabilities		$ 0