Debt (Details) - USD ($) $ in Millions	Oct. 31, 2015	Jun. 30, 2015	Apr. 30, 2015
Debt Instrument [Line Items]
Long-term debt, including current portion	$ 1,479		$ 993
Current portion of long-term debt	250		250
Long-term debt	$ 1,229		$ 743
Two Point Five Percent Notes Due In Fiscal Two Thousand Sixteen [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.50%		2.50%
Long-term debt, including current portion	$ 250		$ 250
One Point Zero Percent Notes Due in Fiscal Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.00%		1.00%
Long-term debt, including current portion	$ 249		$ 248
Two Point Two Five Percent Notes Due in Fiscal Two Thousand Twenty Three [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.25%		2.25%
Long-term debt, including current portion	$ 247		$ 247
Three Point Seven Five Percent Notes Due in Fiscal Two Thousand Forty Three [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%		3.75%
Long-term debt, including current portion	$ 248		$ 248
Four Point Five Percent Notes Due in Fiscal Two Thousand Forty Six [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	4.50%	4.50%	4.50%
Long-term debt, including current portion	$ 485		$ 0
Debt Instrument, Unamortized Discount	10
Unamortized Debt Issuance Expense	$ 5

Face (par) amount of debt instrument at time of issuance.

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-Publisher FASB

-Name Accounting Standards Codification

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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