CONDENSED STATEMENTS OF CONSOLIDATED INCOME (Unaudited) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Statements of Consolidated Income (Unaudited) [Abstract]
Revenues	$ 1,171	$ 1,250	$ 4,494	$ 4,979
Expenses:
Natural gas	735	808	2,989	3,521
Operation and maintenance	227	238	704	684
Depreciation and amortization	65	61	196	184
Taxes other than income taxes	33	32	120	130
Total	1,060	1,139	4,009	4,519
Operating Income	111	111	485	460
Other Income (Expense):
Interest and other finance charges	(48)	(52)	(142)	(155)
Equity in earnings of unconsolidated affiliates	8	10	22	22
Other, net	(1)	(1)	1	(1)
Total	(41)	(43)	(119)	(134)
Income Before Income Taxes	70	68	366	326
Income tax expense	27	26	143	145
Net Income	$ 43	$ 42	$ 223	$ 181