Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=68048583&loc=d3e3636-108311

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Related Party Transactions (GenOn, GenOn Americas Generation and GenOn Mid-Atlantic) - Schedule of Costs Incurred (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Affiliated Entity
Related Party Transaction
General and administrative	$ 14	$ 46	$ 100	$ 139
GenOn Americas Generation \| Genon
Related Party Transaction
Total allocated costs	9	21	52	64
GenOn Americas Generation \| Affiliated Entity
Related Party Transaction
General and administrative	9	21	53	62
GenOn Americas Generation \| Allocated cost of operations \| Genon
Related Party Transaction
Total allocated costs	0	0	(1)	2
GenOn Mid-Atlantic \| Genon
Related Party Transaction
Total allocated costs	5	16	44	47
GenOn Mid-Atlantic \| Affiliated Entity
Related Party Transaction
General and administrative	4	15	42	45
GenOn Mid-Atlantic \| Allocated cost of operations \| Genon
Related Party Transaction
Total allocated costs	$ 1	$ 1	$ 2	$ 2