Fair Value Measurements (Available for Sale Securities) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Realized gains	$ 194	$ 211	$ 246
Realized losses	87	115	88
Proceeds from sale and maturity of Available-for-sale Securities	4,643	4,092	4,190
FPL [Member]
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Realized gains	70	120	182
Realized losses	43	94	59
Proceeds from sale and maturity of Available-for-sale Securities	3,724	3,349	$ 3,342
Available For Sale Securities: Special Use Funds - Equity Securities [Member]
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Unrealized gains	1,166	1,267
Available For Sale Securities: Special Use Funds - Equity Securities [Member] \| FPL [Member]
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Unrealized gains	863	896
Available for sale securities: Special Use Funds - Debt Securities [Member]
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Unrealized gains	17	66
Unrealized losses	51	7
Fair Value	1,129	542
Available for sale securities: Special Use Funds - Debt Securities [Member] \| FPL [Member]
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Unrealized gains	14	54
Unrealized losses	45	5
Fair Value	$ 861	$ 434

This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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