DEBT (Credit Facility) (Details) - USD ($) $ in Millions			9 Months Ended
		Oct. 06, 2015	Sep. 30, 2015		Sep. 30, 2014	Jul. 02, 2015	Jun. 30, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Total credit available under Credit Facilities			$ 2,600.0
Less: Amounts outstanding under Credit Facilities			1,885.0
Principal amount of commercial paper outstanding			321.1					$ 612.3
Letters of credit outstanding			419.3
Total amount available		$ 2,000.0	724.6	[1]
Net borrowings under facilities			785.0		$ 30.0
Net aggregate proceeds		$ 1,260.0
EUS 364-day Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 750.0
Credit facility maturity date			Mar. 06, 2017
Facility term			364 days
Less: Amounts outstanding under Credit Facilities	[2]
Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 1,975.0
Credit facility maturity date			Sep. 26, 2019
Less: Amounts outstanding under Credit Facilities			$ 1,885.0
Debt, weighted average interest rate (in percentage)			2.13%
Net borrowings under facilities			$ 725.0
Proceeds from lines of credit			12,285.0
Repayments of lines of credit			11,560.0
Credit Facility [Member] | Portion of Credit Facility Due in 2018 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 175.0
Credit facility maturity date			Sep. 26, 2018
364-Day Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 625.0			$ 525.0	$ 650.0
Credit facility maturity date			Jul. 01, 2016
Facility term			364 days
364-Day Credit Facility [Member] | Additional Lender [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 100.0
Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 220.0

[1] On October 6, 2015, we closed a public offering of senior unsecured notes, for net aggregate proceeds of approximately $1.26 billion, after deducting underwriting discounts and commissions and estimated offering expenses and settlement of pre-issuance hedges. We used a portion of the net proceeds from this offering to repay a portion of our outstanding commercial paper and to repay any credit facility borrowings that were outstanding. After the offering on a pro-forma basis the total amount available under the Credit Facilities and the EUS-364 day Credit Facility, less amounts outstanding, is approximately $2.0 billion.

[2] Refer to Note 10. Related Party Transactions for further details regarding the EUS 364-day Credit Facility.