INCOME TAXES (Balance Sheets Display Net Deferred Income Tax Liability) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Deferred Income Taxes - Current Assets	$ 60	$ 34
Deferred Tax Liabilities, Gross, Noncurrent	(482)	(365)
Deferred Tax Liabilities, Net	(422)	(331)
TUCSON ELECTRIC POWER COMPANY
Income Taxes [Line Items]
Deferred Income Taxes - Current Assets	64	37
Deferred Tax Liabilities, Gross, Noncurrent	(421)	(319)
Deferred Tax Liabilities, Net	$ (357)	$ (282)