CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OPERATING ACTIVITIES
Net income	$ 117	$ 77
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	682	741
Deferred income taxes	67	47
Provision for uncollectible accounts	15	25
Long-term debt (premium) discount amortization	(17)	(28)
Net (gain) on early retirement of debt		(8)
Changes in current assets and current liabilities:
Accounts receivable	(38)	(9)
Accounts payable	27	(123)
Accounts receivable and payable-affiliates, net		(307)
Accrued income and other taxes	48	41
Other current assets and other current liabilities, net	(49)	70
Retirement benefits	(30)	(52)
Changes in other noncurrent assets and liabilities	(3)	5
Other, net		(2)
Net cash provided by operating activities	819	477
INVESTING ACTIVITIES
Payments for property, plant and equipment and capitalized software	(347)	(426)
Changes in advances to affiliates	(1,027)	742
Net cash provided by (used in) investing activities	(1,374)	316
FINANCING ACTIVITIES
Payments of long-term debt	(38)	(840)
Changes in notes payable-affiliate	588	(122)
Changes in advances from affiliates	(21)	170
Net cash provided by (used in) financing activities	529	(792)
Net (decrease) increase in cash and cash equivalents	(26)	1
Cash and cash equivalents at beginning of period	87	48
Cash and cash equivalents at end of period	61	49
Supplemental cash flow information:
Income taxes (paid) refunded, net	(33)
Interest (paid) (net of capitalized interest of $5 and $4)	$ (142)	$ (165)