Summarized Financial Information of NEECH - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net cash provided by operating activities	$ 6,336	$ 6,116	$ 5,500
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures, independent power and other investments and nuclear fuel purchases	(9,636)	(8,377)	(7,017)
Capital contributions from NEE	0	0	0
Cash grants under the Recovery Act	335	8	343
Sale of independent power and other investments of NEER	658	52	307
Proceeds from sale or maturity of securities in special use funds and other investments	3,776	4,851	4,621
Purchases of securities in special use funds and other investments	(3,829)	(4,982)	(4,767)
Proceeds from the sale of a noncontrolling interest in subsidiaries	645	345	438
Other - net	(59)	98	(286)
Net cash used in investing activities	(8,110)	(8,005)	(6,361)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuances of long-term debt	5,657	5,772	5,054
Retirements of long-term debt	(3,310)	(3,972)	(4,750)
Proceeds from differential membership investors	1,859	761	978
Proceeds from other short-term debt	500	1,225	500
Repayments of other short-term debt	(662)	(813)	(500)
Net change in commercial paper	(106)	(768)	451
Issuances of common stock - net	537	1,298	633
Dividends on common stock	(1,612)	(1,385)	(1,261)
Dividends to NEE	0	0	0
Other - net	(368)	(235)	(105)
Net cash provided by (used in) financing activities	2,495	1,883	1,000
Net increase (decrease) in cash and cash equivalents	721	(6)	139
Cash and cash equivalents at beginning of year	571	577	438
Cash and cash equivalents at end of year	1,292	571	577
NEE (Guarantor) [Member]
Net cash provided by operating activities	1,897	1,659	1,615
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures, independent power and other investments and nuclear fuel purchases	(1)	0	(1)
Capital contributions from NEE	(745)	(1,480)	(912)
Cash grants under the Recovery Act	0	0	0
Sale of independent power and other investments of NEER	0	0	0
Proceeds from sale or maturity of securities in special use funds and other investments	0	0	0
Purchases of securities in special use funds and other investments	0	0	0
Proceeds from the sale of a noncontrolling interest in subsidiaries	0	0	0
Other - net	0	0	10
Net cash used in investing activities	(746)	(1,480)	(903)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuances of long-term debt	0	0	0
Retirements of long-term debt	0	0	0
Proceeds from differential membership investors	0	0	0
Proceeds from other short-term debt	0	0	0
Repayments of other short-term debt	0	0	0
Net change in commercial paper	0	0	0
Issuances of common stock - net	537	1,298	633
Dividends on common stock	(1,612)	(1,385)	(1,261)
Dividends to NEE	0	0	0
Other - net	(75)	(92)	(84)
Net cash provided by (used in) financing activities	(1,150)	(179)	(712)
Net increase (decrease) in cash and cash equivalents	1	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	1	0	0
NEECH [Member]
Net cash provided by operating activities	2,171	2,488	1,976
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures, independent power and other investments and nuclear fuel purchases	(5,701)	(4,744)	(3,741)
Capital contributions from NEE	0	0	0
Cash grants under the Recovery Act	335	8	343
Sale of independent power and other investments of NEER	658	52	307
Proceeds from sale or maturity of securities in special use funds and other investments	1,281	1,120	1,272
Purchases of securities in special use funds and other investments	(1,323)	(1,190)	(1,321)
Proceeds from the sale of a noncontrolling interest in subsidiaries	645	345	438
Other - net	(40)	106	(64)
Net cash used in investing activities	(4,145)	(4,303)	(2,766)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuances of long-term debt	5,349	4,689	4,057
Retirements of long-term debt	(3,048)	(3,421)	(4,395)
Proceeds from differential membership investors	1,859	761	978
Proceeds from other short-term debt	0	1,125	500
Repayments of other short-term debt	(212)	(813)	(500)
Net change in commercial paper	(318)	318	(487)
Issuances of common stock - net	0	0	0
Dividends on common stock	0	0	0
Dividends to NEE	(650)	(698)	812
Other - net	(294)	(162)	(31)
Net cash provided by (used in) financing activities	2,686	1,799	934
Net increase (decrease) in cash and cash equivalents	712	(16)	144
Cash and cash equivalents at beginning of year	546	562	418
Cash and cash equivalents at end of year	1,258	546	562
Other [Member]
Net cash provided by operating activities	2,268	1,969	1,909
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures, independent power and other investments and nuclear fuel purchases	(3,934)	(3,633)	(3,275)
Capital contributions from NEE	745	1,480	912
Cash grants under the Recovery Act	0	0	0
Sale of independent power and other investments of NEER	0	0	0
Proceeds from sale or maturity of securities in special use funds and other investments	2,495	3,731	3,349
Purchases of securities in special use funds and other investments	(2,506)	(3,792)	(3,446)
Proceeds from the sale of a noncontrolling interest in subsidiaries	0	0	0
Other - net	(19)	(8)	(232)
Net cash used in investing activities	(3,219)	(2,222)	(2,692)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuances of long-term debt	308	1,083	997
Retirements of long-term debt	(262)	(551)	(355)
Proceeds from differential membership investors	0	0	0
Proceeds from other short-term debt	500	100	0
Repayments of other short-term debt	(450)	0	0
Net change in commercial paper	212	(1,086)	938
Issuances of common stock - net	0	0	0
Dividends on common stock	0	0	0
Dividends to NEE	650	698	(812)
Other - net	1	19	10
Net cash provided by (used in) financing activities	959	263	778
Net increase (decrease) in cash and cash equivalents	8	10	(5)
Cash and cash equivalents at beginning of year	25	15	20
Cash and cash equivalents at end of year	$ 33	$ 25	$ 15