Consolidated Statements of Cash Flows - NPC - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Net Income (Loss) Attributable to Parent	$ 2,198	$ 2,062
Deferred income taxes and amortization of investment tax credits	573	546
Allowance for equity funds	(59)	(147)
Increase (Decrease) in Regulatory Assets and Liabilities	17	41
Other Noncash Income (Expense)	13	(60)
Increase (Decrease) in Accounts Receivable and Other Operating Assets	(98)	(348)
Accrued property, income and other taxes	390	713
Accounts payable and other liabilities	170	183
Net cash flows from operating activities	5,118	4,824
Capital expenditures	(3,179)	(3,521)
Acquisitions, net of cash acquired	(1,102)	(66)
Payments for (Proceeds from) Other Investing Activities	12	47
Net cash flows from investing activities	(4,373)	(4,117)
Proceeds from Issuance of Long-term Debt	91	0
Repayments of Long-term Debt	(1,344)	(1,500)
Net cash flows from financing activities	(330)	(792)
Net change in cash and cash equivalents	421	(90)
Cash and cash equivalents at end of period	1,142	1,018
Cash and cash equivalents at beginning of period	721	1,108
Nevada Power Company [Member]
Net Income (Loss) Attributable to Parent	263	257
Other Nonrecurring (Income) Expense	(1)	0
Utilities Operating Expense, Depreciation and Amortization	231	227
Deferred income taxes and amortization of investment tax credits	61	52
Allowance for equity funds	(1)	(3)
Increase (Decrease) in Regulatory Assets and Liabilities	25	139
Deferred Energy Change	(22)	(3)
Amortization of Deferred Charges	13	(87)
Other Noncash Income (Expense)	(1)	3
Increase (Decrease) in Accounts Receivable and Other Operating Assets	(122)	(96)
Increase (Decrease) in Inventories	6	7
Accrued property, income and other taxes	11	98
Accounts payable and other liabilities	9	7
Net cash flows from operating activities	472	601
Capital expenditures	(202)	(249)
Acquisitions, net of cash acquired	(77)	0
Payments for (Proceeds from) Other Investing Activities	(4)	0
Net cash flows from investing activities	(275)	(249)
Repayments of Long-term Debt	(86)	(221)
Payments of Ordinary Dividends, Common Stock	(412)	(365)
Net cash flows from financing activities	(407)	(586)
Net change in cash and cash equivalents	(210)	(234)
Cash and cash equivalents at end of period	69	302
Cash and cash equivalents at beginning of period	$ 279	$ 536