Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 57	$ 112
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	186	188
Expenses related to Cascade Crossing	52	0
(Decrease) increase in net liabilities from price risk management activities	(35)	(142)
Regulatory deferral - price risk management activities	35	140
Deferred income taxes	(2)	70
Pension and other postretirement benefits	28	22
Regulatory deferral of settled derivative instruments	13	1
Decoupling mechanism deferrals, net of amortization	5	(1)
Power cost deferrals, net of amortization	(4)	(4)
Allowance for equity funds used during construction	(8)	(4)
Other non-cash income and expenses, net	18	15
Changes in working capital:
Decrease in receivables	47	41
Decrease (increase) in margin deposits, net	10	27
Income tax refund received	0	8
Decrease in payables and accrued liabilities	13	(42)
Other working capital items, net	24	23
Proceeds received from Trojan spent fuel legal settlement	44	0
Other, net	(14)	(6)
Net cash provided by operating activities	459	450
Cash flows from investing activities:
Capital expenditures	(453)	(218)
Proceeds from sale of solar power facility	0	10
Contribution to nuclear decommissioning trust	(44)	0
Sales of nuclear decommissioning trust securities	20	18
Purchases of nuclear decommissioning trust securities	(21)	(19)
Proceeds received from insurance recovery	3	0
Other, net	4	0
Net cash used in investing activities	(491)	(209)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	225	0
Payments on long-term debt	100	0
Proceeds from issuance of common stock, net of issuance costs	67	0
Borrowings on short-term debt	35	0
Payments on short-term debt	(35)	0
Maturities of commercial paper, net	(17)	(30)
Dividends paid	(62)	(61)
Debt issuance costs	(2)	0
Net cash used in financing activities	111	(91)
Increase in cash and cash equivalents	79	150
Cash and cash equivalents, beginning of period	12	6
Cash and cash equivalents, end of period	91	156
Supplemental cash flow information is as follows:
Cash paid for interest, net of amounts capitalized	57	61
Cash paid for income taxes	9	6
Non-cash investing and financing activities:
Accrued dividends payable	22	21
Accrued capital additions	23	15
Preliminary engineering transferred to Construction work in progress from Other noncurrent assets	$ 9	$ 0