Fair Value Measurements (Reconciliation of Changes in the Fair Value) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Realized and unrealized gains (losses): [Abstract]
Realized and unrealized gains (losses) reflected in operating revenues	$ 202	$ (49)	$ 248	$ (453)
Fair Value Net Assets Liabilities Measured On Recurring Basis Gain Loss Included In Interest Expense			5	(41)
Unrealized gains (losses) reflected in operating revenues related to derivatives still held at the reporting date	184	(49)	219	(219)
Financial Instruments, Net [Member]
Reconciliation of changes in fair value based on significant unobservable inputs Roll Forward [Abstract]
Fair value based on significant unobservable inputs, beginning balance	451	460	622	622
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	224	(73)	254	(496)
Included in other comprehensive income	(7)	0	8	0
Included in regulatory assets and liabilities	5	1	4	5
Purchases	61	10	83	14
Settlements	(80)	38	(267)	304
Issuances	(112)	(75)	(132)	(94)
Transfers in	1	9	(18)	16
Transfers out	1	(16)	(10)	(17)
Fair value based on significant unobservable inputs, ending balance	544	354	544	354
The amount of gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to derivatives still held at the reporting date	206	(73)	224	(260)
FPL [Member] | Financial Instruments, Net [Member]
Reconciliation of changes in fair value based on significant unobservable inputs Roll Forward [Abstract]
Fair value based on significant unobservable inputs, beginning balance	(1)	3	5	0
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	0	0	0	0
Included in other comprehensive income	0	0	0	0
Included in regulatory assets and liabilities	5	1	4	5
Purchases	0	0	0	0
Settlements	0	(1)	(5)	(2)
Issuances	0	0	0	0
Transfers in	0	0	0	0
Transfers out	0	0	0	0
Fair value based on significant unobservable inputs, ending balance	4	3	4	3
The amount of gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to derivatives still held at the reporting date	$ 0	$ 0	$ 0	$ 0