COMMON EQUITY (Details) (USD $) In Millions	3 Months Ended				9 Months Ended					1 Months Ended	9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010	May 31, 2010 Common Stock	Sep. 30, 2011 Common Stock	Sep. 30, 2010 Common Stock
Changes in common equity
Balance at the beginning of the period											$ 3,702	$ 3,408
Common stock issued											73	127
Dividends declared											(188)	(180)
Comprehensive income	74	[1]	79	[1]	251	[1]	229	[1]			251	229
Balance at the end of the period											$ 3,838	$ 3,584
Number of shares underlying forward sales contracts (in shares)										6.6
Authorized shares of common stock (in shares)	200				200				150
Outstanding shares of common stock	129.3				129.3				127.4

[1] Accumulated other comprehensive loss totaled $84.6 million as of September 30, 2011 and $46.6 million as of December 31, 2010.