Subsequent Event	6 Months Ended
Jan. 31, 2016
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On February 1, 2016 we entered into a credit agreement with certain institutional lenders for a new five-year credit facility in an aggregate principal amount of $1.5 billion. The credit agreement replaces our February 2012 unsecured revolving credit facility which was due to expire on February 17, 2017 and was terminated on February 1, 2016. The new credit agreement provides for a $500 million unsecured term loan and a $1 billion unsecured revolving credit facility that will expire on February 1, 2021. We may, subject to certain customary conditions, on one or more occasions increase commitments under the credit facility in an amount not to exceed $750 million in the aggregate and may extend the maturity date of the unsecured revolving credit facility up to two times. Advances under the unsecured revolving credit facility accrue interest at rates that are equal to, at our election, either Bank of America's alternate base rate plus a margin that ranges from 0.0% to 0.5% or the London Interbank Offered Rate (LIBOR) plus a margin that ranges from 0.9% to 1.5%. The unsecured term loan accrues interest at rates that are equal to, at our election, either Bank of America's alternate base rate plus a margin that ranges from 0.125% to 0.875% or LIBOR plus a margin that ranges from 1.125% to 1.875%. Actual margins under all of these elections are based on our senior debt credit ratings. The credit agreement includes customary affirmative and negative covenants, including financial covenants that require us to maintain a ratio of total debt to annual earnings before interest, taxes, depreciation and amortization (EBITDA) of not greater than 3.25 to 1.00 as of any date and a ratio of annual EBITDA to annual interest expense of not less than 3.00 to 1.00 as of the last day of each fiscal quarter. The unsecured term loan is subject to quarterly principal payments of 2.5% of the loan amount beginning in July 2017, with the balance payable on the maturity date. On February 1, 2016 we borrowed $250 million on the unsecured revolving credit facility.

Subsequent Event

On February 1, 2016 we entered into a credit agreement with certain institutional lenders for a new five-year credit facility in an aggregate principal amount of $1.5 billion. The credit agreement replaces our February 2012 unsecured revolving credit facility which was due to expire on February 17, 2017 and was terminated on February 1, 2016. The new credit agreement provides for a $500 million unsecured term loan and a $1 billion unsecured revolving credit facility that will expire on February 1, 2021. We may, subject to certain customary conditions, on one or more occasions increase commitments under the credit facility in an amount not to exceed $750 million in the aggregate and may extend the maturity date of the unsecured revolving credit facility up to two times. Advances under the unsecured revolving credit facility accrue interest at rates that are equal to, at our election, either Bank of America's alternate base rate plus a margin that ranges from 0.0% to 0.5% or the London Interbank Offered Rate (LIBOR) plus a margin that ranges from 0.9% to 1.5%. The unsecured term loan accrues interest at rates that are equal to, at our election, either Bank of America's alternate base rate plus a margin that ranges from 0.125% to 0.875% or LIBOR plus a margin that ranges from 1.125% to 1.875%. Actual margins under all of these elections are based on our senior debt credit ratings. The credit agreement includes customary affirmative and negative covenants, including financial covenants that require us to maintain a ratio of total debt to annual earnings before interest, taxes, depreciation and amortization (EBITDA) of not greater than 3.25 to 1.00 as of any date and a ratio of annual EBITDA to annual interest expense of not less than 3.00 to 1.00 as of the last day of each fiscal quarter. The unsecured term loan is subject to quarterly principal payments of 2.5% of the loan amount beginning in July 2017, with the balance payable on the maturity date. On February 1, 2016 we borrowed $250 million on the unsecured revolving credit facility.