INCOME TAXES - Items Excluded from Effective Income Tax Rates (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012 Income taxes on postretirement plan amendment discussed in Note 5	Mar. 31, 2012 Income taxes on postretirement plan amendment discussed in Note 5	Mar. 31, 2012 State income tax settlements	Jun. 30, 2012 Income tax settlements
Income tax credit (charge) that is excluded from the company's effective income tax rate	$ 0	$ (18)	$ (18)	$ 8	$ (3)