Derivative Instruments and Hedging Activity (Tables)

9 Months Ended

Sep. 30, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of the fair values of derivative instruments designated as cash flow hedging instruments included in balance sheets

Fair Value of Derivative Instruments - The tables below present NEP's gross derivative positions, based on the total fair value of each derivative instrument, at September 30, 2017 and December 31, 2016, as required by disclosure rules, as well as the location of the net derivative positions, based on the expected timing of future payments, on the condensed consolidated balance sheets.

	September 30, 2017
	Gross Basis				Net Basis
	Assets		Liabilities		Assets		Liabilities
	(millions)
Interest rate contracts	$	3	$	40	$	16	$	53
Foreign currency contracts	—		3		—		3
Total fair values	$	3	$	43	$	16	$	56
Net fair value by balance sheet line item:
Other current assets					$	10
Other non-current assets					6
Current derivative liabilities							$	15
Other non-current liabilities							41
Total derivatives					$	16	$	56

	December 31, 2016
	Gross Basis				Net Basis
	Assets		Liabilities		Assets		Liabilities
	(millions)
Interest rate contracts	$	15	$	44	$	17	$	46
Foreign currency contracts	1		—		1		—
Total fair values	$	16	$	44	$	18	$	46
Net fair value by balance sheet line item:
Other current assets					$	1
Other non-current assets					17
Current derivative liabilities							$	18
Other non-current liabilities							28
Total derivatives					$	18	$	46

Schedule of gains (losses) related to interest rate contracts

Gains (losses) related to NEP's interest rate contracts are recorded in the condensed consolidated financial statements as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
	(millions)
Interest rate contracts:
Losses reclassified from AOCI to interest expense	$	(1	)	$	(2	)	$	(6	)	$	(6	)
Gains (losses) recognized in interest expense	$	(1	)	$	1		$	(21	)	$	(83	)