Derivative Instruments (Reconciliation of Changes in the Fair Value) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Realized and unrealized gains (losses): [Abstract]
Fair value based on significant unobservable inputs, ending balance	$ (448)	$ 1,150	$ (448)	$ 1,150
Derivative Financial Instruments, Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value based on significant unobservable inputs, beginning balance	584	1,305	1,374	1,207
Realized and unrealized gains (losses): [Abstract]
Included in earnings	(1,138)	(55)	(1,795)	294
Included in other comprehensive income			0	1
Included in regulatory assets and liabilities	1	(1)	2	(3)
Purchases	62	37	153	157
Sales			0	114
Settlements	80	(108)	(54)	(490)
Issuances	(52)	(26)	(116)	(98)
Transfers in			1	0
Transfers out	15	(2)	(13)	(32)
Fair value based on significant unobservable inputs, ending balance		1,150		1,150
Gains (losses) included in earnings attributable to the change in unrealized gains (losses) relating to derivatives held at the reporting date	(1,107)	(46)	(1,581)	79
Realized and unrealized gains (losses) reflected in operating revenues			(1,794)	314
Unrealized gains (losses) reflected in operating revenues, for derivatives still held at the reporting date	(1,107)	(46)	(1,581)	90
FPL [Member]
Realized and unrealized gains (losses): [Abstract]
Fair value based on significant unobservable inputs, ending balance	(1)	(6)	(1)	(6)
FPL [Member] | Derivative Financial Instruments, Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value based on significant unobservable inputs, beginning balance	0	(6)	(1)	(8)
Realized and unrealized gains (losses): [Abstract]
Included in earnings	0	0	0	0
Included in other comprehensive income			0	0
Included in regulatory assets and liabilities	1	(1)	2	(3)
Purchases	0	0	0	0
Sales			0	0
Settlements	(2)	1	(2)	5
Issuances	0	0	0	0
Transfers in			0	0
Transfers out	0	0	0	0
Fair value based on significant unobservable inputs, ending balance		(6)		(6)
Gains (losses) included in earnings attributable to the change in unrealized gains (losses) relating to derivatives held at the reporting date	0	$ 0	0	$ 0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 2,281		$ 2,281