CONDENSED STATEMENTS OF CONSOLIDATED INCOME (Unaudited) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Statement [Abstract]
Revenues	$ 6,102	$ 6,569	$ 6,257
Expenses:
Natural gas	4,055	4,574	4,371
Operation and maintenance	964	913	922
Depreciation and amortization	262	248	229
Taxes other than income taxes	159	167	166
Total	5,440	5,902	5,688
Operating Income	662	667	569
Other Income (Expense):
Interest and other finance charges	(190)	(208)	(213)
Equity in earnings of unconsolidated affiliates	30	29	15
Other, net	1	(1)	5
Total	(159)	(180)	(193)
Income Before Income Taxes	503	487	376
Income tax expense	187	187	146
Net Income	$ 316	$ 300	$ 230