CONDENSED STATEMENTS OF CONSOLIDATED INCOME (Unaudited) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Condensed Statements of Consolidated Income (Unaudited) [Abstract]
Revenues	$ 1,228	$ 1,191	$ 3,323	$ 3,729
Expenses:
Natural gas	778	778	2,254	2,713
Operation and maintenance	237	214	477	446
Depreciation and amortization	65	63	131	123
Taxes other than income taxes	34	35	87	98
Total	1,114	1,090	2,949	3,380
Operating Income	114	101	374	349
Other Income (Expense):
Interest and other finance charges	(45)	(52)	(94)	(103)
Equity in earnings of unconsolidated affiliates	8	7	14	12
Other, net	1	0	2	0
Total	(36)	(45)	(78)	(91)
Income Before Income Taxes	78	56	296	258
Income tax expense	31	23	116	119
Net Income	$ 47	$ 33	$ 180	$ 139