OTHER FINANCIAL DATA - SHARE-BASED COMPENSATION (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allocated Share Based Compensation Expense Net Of Tax	$ 7	$ 8
IENova Plans [Member] [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units granted	183,970
Service-Based [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units granted	93,256
Performance-Based, Total Shareholder Return [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units granted	372,270
Performance-Based, Earnings Per Share [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units granted	94,550