EMPLOYEE BENEFIT PLANS - FUNDED STATUS (DETAILS) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Qualified Defined Benefit [Member]
Benefit obligation
Beginning of year	$ 1,594	$ 1,343
Service cost	38	35	32
Interest cost	73	73	68
Plan amendments	0	21
Actuarial (gain) loss	214	206
Benefits paid	(46)	(42)
End of year	1,873	1,594	1,343
Accumulated benefit obligation	1,733	1,483
Plan assets at fair value
Beginning of year	1,288	1,143
Actual return on plan assets	186	54
Employer contributions	110	133
Benefits paid	(46)	(42)
End of year	1,538	1,288	1,143
Funded status (unfunded)	(335)	(306)
Percent funded	82.00%	81.00%
Nonqualified Defined Benefit [Member]
Benefit obligation
Beginning of year	43	41
Service cost	1	1	1
Interest cost	2	2	2
Plan amendments	0	(1)
Actuarial (gain) loss	(2)	3
Benefits paid	(2)	(5)
End of year	42	43	41
Accumulated benefit obligation	41	42
Plan assets at fair value
Beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	2	5
Benefits paid	(2)	(5)
End of year	0	0	0
Funded status (unfunded)	(42)	(43)
Postretirement Medical Benefits [Member]
Benefit obligation
Beginning of year	120	133
Service cost	5	6	5
Interest cost	5	7	7
Actuarial (gain) loss	(11)	(23)
Benefits paid	(2)	(3)
End of year	117	120	133
Plan assets at fair value
Beginning of year	0	0
Employer contributions	2	3
Benefits paid	(2)	(3)
End of year	0	0	0
Funded status (unfunded)	$ (117)	$ (120)