INCOME TAXES (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current taxes:
Federal	$ 52	$ (47)	$ 63
State	10	1	(6)
Total current taxes	62	(46)	57
Deferred taxes, net:
Federal	122	223	94
State	12	13	8
Total deferred taxes	134	236	102
Investment tax credits:
Deferred - state			20
Amortization of amounts deferred - state	(25)	(28)	(9)
Amortization of amounts deferred federal	(3)	(3)	(3)
Total investment tax credits	(28)	(31)	8
Total income tax expense	$ 168	$ 159	$ 167