Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 48	$ 49
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	62	62
(Decrease) increase in net liabilities from price risk management activities	(37)	21
Regulatory deferral - price risk management activities	37	(22)
Deferred income taxes	13	24
Pension and other postretirement benefits	10	7
Regulatory deferral of settled derivative instruments	5	2
Decoupling mechanism deferrals, net of amortization	(5)	3
Power cost deferrals, net of amortization	(2)	3
Allowance for equity funds used during construction	(2)	(1)
Other non-cash income and expenses, net	10	7
Changes in working capital:
Decrease in receivables	29	9
Decrease (increase) in margin deposits, net	13	(18)
Income tax refund received	0	8
Decrease in payables and accrued liabilities	(4)	(18)
Other working capital items, net	(12)	(24)
Other, net	0	(2)
Net cash provided by operating activities	165	110
Cash flows from investing activities:
Capital expenditures	(108)	(69)
Proceeds from sale of solar power facility	0	10
Sales of nuclear decommissioning trust securities	8	7
Purchases of nuclear decommissioning trust securities	(9)	(7)
Other, net	2	1
Net cash used in investing activities	(107)	(58)
Cash flows from financing activities:
Maturities of commercial paper, net	(17)	(30)
Dividends paid	(20)	(20)
Net cash used in financing activities	(37)	(50)
Increase in cash and cash equivalents	21	2
Cash and cash equivalents, beginning of period	12	6
Cash and cash equivalents, end of period	33	8
Supplemental cash flow information is as follows:
Cash paid for interest, net of amounts capitalized	13	13
Non-cash investing and financing activities:
Accrued dividends payable	20	21
Accrued capital additions	11	8
Preliminary engineering transferred to Construction work in progress from Other noncurrent assets	$ 4	$ 0