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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

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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.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64852052&loc=d3e1703-114919

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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- References

No definition available.

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- Definition

Amount of cost for defined contribution plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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Employee Retirement Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Target asset allocations [Abstract]
Defined contribution expense	$ 53	$ 52	$ 63
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	241	325
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ 1,427	$ 1,177
Weighted-average assumptions used to determine benefit obligations [Abstract]
Discount rate (in hundredths)	3.59%	4.09%
Salary increase (in hundredths)	4.10%	4.10%
Pension Benefits [Member] \| Equity Securities [Member]
Target asset allocations [Abstract]
Equity investments, target allocation percentage (in hundredths)	45.00%
Pension Benefits [Member] \| Debt Securities [Member]
Target asset allocations [Abstract]
Equity investments, target allocation percentage (in hundredths)	32.00%
Pension Benefits [Member] \| Alternative Investments [Member]
Target asset allocations [Abstract]
Equity investments, target allocation percentage (in hundredths)	13.00%
Pension Benefits [Member] \| Convertible Securities [Member]
Target asset allocations [Abstract]
Equity investments, target allocation percentage (in hundredths)	10.00%
FPL[Member]
Target asset allocations [Abstract]
Defined contribution expense	$ 33	$ 32	$ 40
FPL[Member] \| Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	208	222
FPL[Member] \| Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ 1,351	$ 1,301