Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 15	$ 18	$ 31	$ 36
Interest cost	26	25	52	49
Expected return on plan assets	(65)	(64)	(130)	(127)
Amortization of prior service cost (benefit)	1	1	1	1
Amortization of losses	0	0	0	0
Net periodic benefit (income) cost	(23)	(20)	(46)	(41)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	0	0	1	1
Interest cost	4	4	7	7
Expected return on plan assets	0	(1)	0	(1)
Amortization of prior service cost (benefit)	(1)	(1)	(2)	(1)
Amortization of losses	0	1	0	1
Net periodic benefit (income) cost	3	3	6	7
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(14)	(13)	(29)	(27)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ 3	$ 2	$ 5	$ 5