Consolidated Statements of Cash Flows - NPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net Income (Loss) Attributable to Parent	$ 490	$ 469
Deferred income taxes and amortization of investment tax credits	72	206
Allowance for equity funds	(15)	(31)
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 end of period	1,086	507
Cash and cash equivalents at beginning of period	1,108	617
Nevada Power Company [Member]
Net Income (Loss) Attributable to Parent	3	24
Other Nonrecurring (Income) Expense	0	(3)
Utilities Operating Expense, Depreciation and Amortization	75	74
Deferred income taxes and amortization of investment tax credits	2	13
Allowance for equity funds	(1)	(1)
Increase (Decrease) in Regulatory Assets and Liabilities	7	1
Deferred Energy Change	23	39
Amortization of Deferred Charges	(14)	16
Other Noncash Income (Expense)	0	16
Increase (Decrease) in Accounts Receivable and Other Operating Assets	(47)	18
Increase (Decrease) in Inventories	0	2
Accounts payable and other liabilities	(19)	(35)
Net cash flows from operating activities	123	92
Payments to Acquire Property, Plant, and Equipment	98	63
Proceeds from Sale of Other Property, Plant, and Equipment	0	4
Payments for (Proceeds from) Other Investing Activities	0	(10)
Net cash flows from investing activities	(98)	(49)
Repayments of Long-term Debt	214	252
Repayments of Short-term Debt	0	(30)
Net cash flows from financing activities	(214)	(222)
Net change in cash and cash equivalents	(189)	(179)
Cash and cash equivalents at end of period	347	41
Cash and cash equivalents at beginning of period	$ 536	$ 220