Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 132	$ 121
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	244	227
(Decrease) increase in net liabilities from price risk management activities	(59)	71
Regulatory deferrals-price risk management activities	59	(71)
Deferred income taxes	18	31
Pension and other postretirement benefits	21	25
Allowance for equity funds used during construction	(19)	(15)
Other non-cash income and expenses, net	8	29
Changes in working capital:
Decrease in accounts receivable and unbilled revenues	53	37
Decrease (increase) in inventories	1	(12)
Decrease (increase) in margin deposits, net	25	(9)
Increase in accounts payable and accrued liabilities	31	13
Other working capital items, net	12	15
Other, net	(29)	(23)
Net cash provided by operating activities	497	439
Cash flows from investing activities:
Capital expenditures	(454)	(452)
Distribution from Nuclear decommissioning trust	0	(50)
Sales tax refund received related to Tucannon River Wind Farm	0	23
Sales of Nuclear decommissioning trust securities	17	11
Purchases of Nuclear decommissioning trust securities	(16)	(10)
Other, net	(1)	1
Net cash used in investing activities	(454)	(377)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	0	271
Proceeds from issuance of long-term debt	265	145
Payments on long-term debt	(133)	(442)
Change in short-term debt	(6)	0
Dividends paid	(82)	(70)
Other	(3)	(1)
Net cash provided by (used in) financing activities	41	(97)
Increase (Decrease) in cash and cash equivalents	84	(35)
Cash and cash equivalents, beginning of period	4	127
Cash and cash equivalents, end of period	88	92
Supplemental cash flow information is as follows:
Cash paid for interest, net of amounts capitalized	61	67
Cash paid for income taxes	12	3
Non-cash investing and financing activities:
Assets obtained under capital lease	$ 57	$ 0