PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Actual Returns on Assets Held by Our Pension Trusts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Actual return on plan assets	$ 490	$ 49	$ 515
Direct investments
Defined Benefit Plan Disclosure [Line Items]
Actual return on plan assets	324	48	362
Derivatives
Defined Benefit Plan Disclosure [Line Items]
Actual return on plan assets	$ 166	$ 1	$ 153