TRANSACTIONS WITH MAJOR CUSTOMERS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Transactions with major customers
Revenues	$ 87	$ 80	$ 82	$ 87	$ 88	$ 85	$ 82	$ 86	$ 336	$ 341	[1]	$ 343	[1]
Accounts receivable and other	35				37				35	37
Total revenues | Major customers | Anadarko Energy Services Company
Transactions with major customers
Revenues									48	48		48
Total revenues | Major customers | Pacific Gas and Electric Company
Transactions with major customers
Revenues									45	46		47
Accounts receivable and other | Amounts owed by major customers | Anadarko Energy Services Company
Transactions with major customers
Accounts receivable and other	4				4				4	4
Accounts receivable and other | Amounts owed by major customers | Pacific Gas and Electric Company
Transactions with major customers
Accounts receivable and other	$ 4				$ 4				$ 4	$ 4

[1] Recast as discussed in Note 2 and Note 6.