Summary of Significant Accounting and Reporting Policies (Details) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended	9 Months Ended
		Oct. 28, 2015	May. 12, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014		Dec. 31, 2014		Jul. 01, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Restricted cash				$ 16	$ 16			$ 82	[1]
Restricted cash, noncurrent				$ 3	3			3
Common units sold in private placement			2,594,948
NEE purchase of NEP OpCo's common units			$ 109		702	$ 0
Proceeds from issuance of common units					702	$ 0	[2]
Common units sold in public offering				8,375,907
Aggregate purchase price of common units sold in public offering				$ 218
Property, plant and equipment, net				3,145	3,145			3,276	[1]
Deferral related to differential membership interests - VIEs				419	419			428	[1]
Investments in equity method investees - VIEs				18	18			19	[1]
CITC Proceeds Received by Genesis Due to NEECH [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Restricted cash	[1]							22
Variable Interest Entity [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Restricted cash				13	13			55	[1]
Property, plant and equipment, net				707	707			722	[1]
Palo Duro [Member] | Variable Interest Entity [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net				758	758			812
Deferral related to differential membership interests - VIEs				$ 464	$ 464			$ 555
NEP OpCo [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Noncontrolling interest, percent ownership			22.20%	22.60%	22.60%					20.10%
Subsequent Event [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Distribution to unitholders declared (per share)		$ 0.27
Private Placement [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Price per share of common unit sold			$ 41.87
Stock Issuance Costs			$ 3
Public Offering [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Price per share of common unit sold				$ 26.00	$ 26.00
Stock Issuance Costs				$ 5
Term Loan [Member] | Short-term Term Loan Due 2016 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Principal Amount				$ 313	$ 313
Subsidiary of NEE [Member] | NEP OpCo [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Common units sold in private placement				27,000,000
NEE purchase of NEP OpCo's common units				$ 702
Proceeds from issuance of common units				$ 110

[1] Prior-period financial information has been retrospectively adjusted as discussed in Note 2.

[2] Prior-period financial information has been retrospectively adjusted as discussed in Note 2.