Consolidated Statements of Cash Flows - SPPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net Income (Loss) Attributable to Parent	$ 490	$ 469
Increase (Decrease) in Allowance for Equity Funds Used During Construction	15	31
Deferred income taxes and amortization of investment tax credits	72	206
Increase (Decrease) in Regulatory Assets and Liabilities	60	152
Other Noncash Income (Expense)	(3)	10
Increase (Decrease) in Accounts Receivable and Other Operating Assets	219	(18)
Accounts payable and other liabilities	(73)	(103)
Net cash flows from operating activities	1,360	1,107
Payments to Acquire Property, Plant, and Equipment	1,027	1,426
Payments for (Proceeds from) Other Investing Activities	39	(41)
Net cash flows from investing activities	(1,284)	(1,455)
Net cash flows from financing activities	(99)	239
Net change in cash and cash equivalents	(22)	(110)
Cash and cash equivalents at beginning of period	1,108	617
Cash and cash equivalents at end of period	1,086	507
Sierra Pacific Power Company [Member]
Net Income (Loss) Attributable to Parent	17	19
Utilities Operating Expense, Depreciation and Amortization	29	28
Increase (Decrease) in Allowance for Equity Funds Used During Construction	(1)	0
Deferred income taxes and amortization of investment tax credits	10	11
Increase (Decrease) in Regulatory Assets and Liabilities	(3)	(4)
Deferred Energy Change	23	26
Amortization of Deferred Charges	(9)	12
Other Noncash Income (Expense)	0	1
Increase (Decrease) in Accounts Receivable and Other Operating Assets	18	(11)
Increase (Decrease) in Inventories	1	0
Accounts payable and other liabilities	(7)	(4)
Net cash flows from operating activities	78	76
Payments to Acquire Property, Plant, and Equipment	48	47
Payments for (Proceeds from) Other Investing Activities	0	(2)
Net cash flows from investing activities	(48)	(45)
Repayments of Long-term Debt	1	0
Net cash flows from financing activities	(1)	0
Net change in cash and cash equivalents	29	31
Cash and cash equivalents at beginning of period	106	22
Cash and cash equivalents at end of period	$ 135	$ 53