Consolidated Statements of Cash Flows - NPC - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Net Income (Loss) Attributable to Parent	$ 1,130	$ 1,026
Deferred income taxes and amortization of investment tax credits	341	291
Allowance for equity funds	(35)	(130)
Increase (Decrease) in Regulatory Assets and Liabilities	21	(1)
Other Noncash Income (Expense)	3	(72)
Increase (Decrease) in Accounts Receivable and Other Operating Assets	(73)	(252)
Accrued property, income and other taxes	(244)	557
Accounts payable and other liabilities	20	94
Net cash flows from operating activities	2,428	2,771
Capital expenditures	(1,813)	(2,103)
Acquisitions, net of cash acquired	(588)	(66)
Payments for (Proceeds from) Other Investing Activities	6	46
Net cash flows from investing activities	(2,437)	(2,455)
Proceeds from Issuance of Long-term Debt	91	0
Repayments of Long-term Debt	(950)	(1,000)
Net cash flows from financing activities	112	(642)
Net change in cash and cash equivalents	106	(330)
Cash and cash equivalents at end of period	827	778
Cash and cash equivalents at beginning of period	721	1,108
Nevada Power Company [Member]
Net Income (Loss) Attributable to Parent	87	69
Other Nonrecurring (Income) Expense	(1)	0
Utilities Operating Expense, Depreciation and Amortization	154	151
Deferred income taxes and amortization of investment tax credits	34	25
Allowance for equity funds	(1)	(3)
Increase (Decrease) in Regulatory Assets and Liabilities	13	17
Deferred Energy Change	(25)	31
Amortization of Deferred Charges	7	(42)
Other Noncash Income (Expense)	(2)	4
Increase (Decrease) in Accounts Receivable and Other Operating Assets	(84)	(70)
Increase (Decrease) in Inventories	7	2
Accrued property, income and other taxes	18	10
Accounts payable and other liabilities	48	50
Net cash flows from operating activities	255	244
Capital expenditures	(139)	(181)
Acquisitions, net of cash acquired	(77)	0
Payments for (Proceeds from) Other Investing Activities	(4)	0
Net cash flows from investing activities	(212)	(181)
Repayments of Long-term Debt	(81)	(217)
Payments of Ordinary Dividends, Common Stock	(322)	(270)
Net cash flows from financing activities	(312)	(487)
Net change in cash and cash equivalents	(269)	(424)
Cash and cash equivalents at end of period	10	112
Cash and cash equivalents at beginning of period	$ 279	$ 536