Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale debt securities.

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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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.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
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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.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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The cash inflow associated with the sale or maturity (principal being due) of securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
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Fair Value Measurements (Available for Sale Securities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Realized Gains	$ 28	$ 35	$ 83	$ 126
Realized Losses	15	21	53	53
Proceeds from Sale and Maturity of Available-for-sale Securities	902	712	2,330	3,642
Unrealized losses on available for sale debt securities			15		$ 51
Fair value of available for sale securities in an unrealized loss position	313		313		1,129
FPL [Member]
Schedule of Available-for-sale Securities [Line Items]
Realized Gains	15	11	42	56
Realized Losses	8	11	30	26
Proceeds from Sale and Maturity of Available-for-sale Securities	661	$ 556	1,741	$ 3,094
Unrealized losses on available for sale debt securities			15		45
Fair value of available for sale securities in an unrealized loss position	$ 259		259		861
Available For Sale Securities: Special Use Funds - Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized gains			1,322		1,166
Available For Sale Securities: Special Use Funds - Equity Securities [Member] \| FPL [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized gains			952		863
available for sale securities: Special Use Funds - Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized gains			61		17
available for sale securities: Special Use Funds - Debt Securities [Member] \| FPL [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized gains			$ 47		$ 14