Fair Value Measurements (Available for Sale Securities) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities[Line Items]
Realized gains	$ 116	$ 194	$ 211
Realized losses	76	87	115
Proceeds from sale and maturity of Available-for-sale Securities	3,400	4,643	4,092
FPL [Member]
Schedule of Available-for-sale Securities[Line Items]
Realized gains	53	70	120
Realized losses	44	43	94
Proceeds from sale and maturity of Available-for-sale Securities	2,442	3,724	$ 3,349
Available For Sale Securities: Special Use Funds - Equity Securities [Member]
Schedule of Available-for-sale Securities[Line Items]
Unrealized gains	1,396	1,166
Available For Sale Securities: Special Use Funds - Equity Securities [Member] \| FPL [Member]
Schedule of Available-for-sale Securities[Line Items]
Unrealized gains	1,007	863
Available for sale securities: Special Use Funds - Debt Securities [Member]
Schedule of Available-for-sale Securities[Line Items]
Unrealized gains	22	17
Unrealized losses	34	51
Fair Value	959	1,129
Available for sale securities: Special Use Funds - Debt Securities [Member] \| FPL [Member]
Schedule of Available-for-sale Securities[Line Items]
Unrealized gains	17	14
Unrealized losses	28	45
Fair Value	$ 722	$ 861

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=73527792&loc=d3e27290-111563

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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 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73527792&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=73527792&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=73527792&loc=d3e27161-111563

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