EMPLOYEE BENEFIT PLANS - NET PENSION EXPENSE (DETAILS) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 38	$ 35	$ 32
Interest cost	73	73	68
Expected return on assets	(93)	(88)	(71)
Amortization of prior service cost	(1)	(1)	(1)
Recognized actuarial (gain) loss	40	23	22
Net pension expense	57	42	50
Nonqualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	1
Interest cost	2	2	2
Expected return on assets	0	0	0
Amortization of prior service cost	0	0	0
Recognized actuarial (gain) loss	1	1	0
Net pension expense	4	4	3
Anticipated funding in 2013	2
Postretirement Medical Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5	6	5
Interest cost	5	7	7
Amortization of prior service cost	1	1	0
Recognized actuarial (gain) loss	(1)	1	0
Net pension expense	10	15	12
Anticipated funding in 2013	4
Minimum [Member] | Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Anticipated funding in 2013	35
Maximum [Member] | Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Anticipated funding in 2013	$ 50