PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Reconciliation of Pension Plan Assets (Details) (Fair Value, Inputs, Level 3, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning	$ 4,181	$ 3,979
Net realized gains (losses)	222	89
Net change in unrealized appreciation (depreciation)	260	(79)
Net purchases, (sales) and (settlements)	(207)	192
Fair value of plan assets, ending	4,456	4,181
Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning	2,436	2,284
Net realized gains (losses)	70	95
Net change in unrealized appreciation (depreciation)	228	(180)
Net purchases, (sales) and (settlements)	37	237
Fair value of plan assets, ending	2,771	2,436
Private equity and related funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning	1,649	1,575
Net realized gains (losses)	146	(6)
Net change in unrealized appreciation (depreciation)	26	122
Net purchases, (sales) and (settlements)	(227)	(42)
Fair value of plan assets, ending	1,594	1,649
Real estate and related funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning	96	120
Net realized gains (losses)	6	0
Net change in unrealized appreciation (depreciation)	6	(21)
Net purchases, (sales) and (settlements)	(17)	(3)
Fair value of plan assets, ending	$ 91	$ 96