NOTES PAYABLE, LONG-TERM DEBT AND AVAILABLE CREDIT FACILITIES NOTES PAYABLE, LONG-TERM DEBT AND AVAILABLE CREDIT FACILITIES (Schedule of Committed and Available Credit Facilities) (Details) - USD ($) $ in Millions	May 31, 2016	Sep. 30, 2017
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 10,880
Line of Credit Facility, Remaining Borrowing Capacity		6,380
$100M Revolving Credit Facility Due 3/2020 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		100
Line of Credit Facility, Remaining Borrowing Capacity		100
$280M Revolving Credit Facility Due 3/2020 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		280
Line of Credit Facility, Remaining Borrowing Capacity		280
DCC Term Loan Facility [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 4,500
Line of Credit Facility, Remaining Borrowing Capacity		0
$100M Revolving Credit Facility Due 8/2018 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		100
Line of Credit Facility, Remaining Borrowing Capacity		100
$200M Revolving Credit Facility Due 7/2018 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		200
Line of Credit Facility, Remaining Borrowing Capacity		200
$200M Revolving Credit Facility Due 5/2018 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		200
Line of Credit Facility, Remaining Borrowing Capacity		200
$200M Revolving Credit Facility due 3/2020 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		200
Line of Credit Facility, Remaining Borrowing Capacity		200
$100M Revolving Credit Facility Due 3/2020 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		100
Line of Credit Facility, Remaining Borrowing Capacity		100
$100M Revolving Credit Facility 1 Due 3/2020 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		100
Line of Credit Facility, Remaining Borrowing Capacity		100
$100M Revolving Credit Facility Due 3/2018 [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		100
Line of Credit Facility, Remaining Borrowing Capacity		100
Five Year Competitive Advance and Revolving Credit Facility Agreement [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		5,000
Line of Credit Facility, Remaining Borrowing Capacity		$ 5,000