DEBT (Schedule of Line of Credit) (Details)	3 Months Ended
	Mar. 31, 2018 USD ($)
Debt [Line Items]
Facility Limit	$ 300,000,000
Letters of Credit Outstanding	0
Commercial Paper	121,000,000
Facility Availability	179,000,000
Letters of credit sublimit	50,000,000
Swingline loans sublimit	$ 100,000,000
Swingline loan repay term	7 days
Utility
Debt [Line Items]
Facility Limit	$ 3,000,000,000
Letters of Credit Outstanding	48,000,000
Commercial Paper	97,000,000
Facility Availability	2,855,000,000
Letters of credit sublimit	500,000,000
Swingline loans sublimit	75,000,000
Credit Facilities
Debt [Line Items]
Facility Limit	3,300,000,000
Letters of Credit Outstanding	48,000,000
Commercial Paper	218,000,000
Facility Availability	$ 3,034,000,000