Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Asset retirement obligation, roll forward analysis [Roll Forward]
Beginning balance	$ 2,736	$ 2,469
Liabilities incurred	76	57
Accretion expense	148	138
Liabilities settled	(14)	(2)
Revision in estimated cash flows - net	85	74
Ending balance	3,031	2,736
Restricted funds included in special use funds [Abstract]
Restricted funds	6,003	5,434
NEER [Member]
Asset retirement obligation, roll forward analysis [Roll Forward]
Beginning balance	817	647
Liabilities incurred	59	56
Accretion expense	52	47
Liabilities settled	(14)	(2)
Revision in estimated cash flows - net	70	69
Ending balance	984	817
Restricted funds included in special use funds [Abstract]
Restricted funds	1,913	1,769
FPL[Member]
Asset retirement obligation, roll forward analysis [Roll Forward]
Beginning balance	1,919	1,822
Liabilities incurred	17	1
Accretion expense	96	91
Liabilities settled	0	0
Revision in estimated cash flows - net	15	5
Ending balance	2,047	1,919
Restricted funds included in special use funds [Abstract]
Restricted funds	4,090	$ 3,665
liabilities associated with assets held-for-sale [Member] \| NEER [Member]
Asset retirement obligation, roll forward analysis [Roll Forward]
Ending balance	$ 13

No definition available.

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848

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- Definition

Carrying amount of an asset that is legally restricted for purposes of settling an asset retirement obligation.

+ References

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- Definition

Amount of asset retirement obligations incurred during the period.

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Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

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- Definition

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 35
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6392603&loc=d3e7123-110846

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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