FAIR VALUE MEASUREMENTS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 574			$ 574			$ 562
Gross unrealized gains	278			278			248
Gross unrealized losses	(5)			(5)			(6)
Estimated fair value	847			847			804
Proceeds from sales	191		48	320		90
Gross realized gains	5		1	9		2
Gross realized losses	(5)		(1)	(5)		(2)
Total Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	284			284			305
Gross unrealized gains	23			23			21
Gross unrealized losses	(1)			(1)			(1)
Estimated fair value	306			306			325
Debt Securities Issued By The U.S. Treasury And Other U.S. Government Corporations And Agencies
Schedule of Available-for-sale Securities [Line Items]
Cost	143	[1]		143	[1]		157
Gross unrealized gains	12	[1]		12	[1]		13
Estimated fair value	155	[1]		155	[1]		170
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	61	[2]		61	[2]		72
Gross unrealized gains	6	[2]		6	[2]		5
Gross unrealized losses	(1)	[2]		(1)	[2]
Estimated fair value	66	[2]		66	[2]		77
Other Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	80	[3]		80	[3]		76
Gross unrealized gains	5	[3]		5	[3]		3
Gross unrealized losses							(1)
Estimated fair value	85	[3]		85	[3]		78
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	242			242			246
Gross unrealized gains	255			255			227
Gross unrealized losses	(4)			(4)			(5)
Estimated fair value	493			493			468
Cash And Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Cost	48			48			11
Estimated fair value	$ 48			$ 48			$ 11

[1] Maturity dates are 2012-2042

[2] Maturity dates are 2012-2057

[3] Maturity dates are 2013-2111