Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 112	$ 118
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	188	170
Increase (decrease) in net liabilities from price risk management activities	(142)	(26)
Regulatory deferral - price risk management activities	140	26
Deferred income taxes	70	40
Pension and other postretirement benefits	22	3
Regulatory deferral of settled derivative instruments	1	15
Power cost deferrals, net of amortization	(4)	17
Renewable adjustment clause deferrals	1	16
Allowance for equity funds used during construction	(4)	(3)
Other non-cash income and expenses, net	15	21
Changes in working capital:
Decrease (increase) in receivables	41	22
(Increase) decrease in margin deposits, net	27	0
Income tax refund received	8	8
Decrease in payables and accrued liabilities	(42)	3
Other working capital items, net	23	13
Contribution to pension plan	0	(26)
Contribution to the voluntary employees’ beneficiary association trust	(2)	(14)
Other, net	(4)	(4)
Net cash provided by operating activities	450	399
Cash flows from investing activities:
Capital expenditures	(218)	(215)
Sale of solar power facility	10	0
Sales of Nuclear decommissioning trust securities	18	39
Purchases of Nuclear decommissioning trust securities	(19)	(41)
Other, net	0	3
Net cash used in investing activities	(209)	(214)
Cash flows from financing activities:
Payments on long-term debt	0	(10)
Maturities of commercial paper, net	(30)	(19)
Dividends paid	(61)	(59)
Noncontrolling interests’ capital distributions	0	(4)
Net cash used in financing activities	(91)	(92)
Increase in cash and cash equivalents	150	93
Cash and cash equivalents, beginning of period	6	4
Cash and cash equivalents, end of period	156	97
Supplemental cash flow information is as follows:
Cash paid for interest, net of amounts capitalized	61	66
Cash paid for income taxes	6	3
Non-cash investing and financing activities:
Accrued capital additions	15	22
Increase to Boardman’s asset retirement obligation and cost basis of plant for updated depreciation study	0	23
Accrued dividends payable	21	21
Preliminary engineering transferred to Construction work in progress from Other noncurrent assets	$ 0	$ 7