Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 16	$ 17	$ 47	$ 53
Interest cost	26	23	78	72
Expected return on plan assets	(65)	(63)	(195)	(190)
Amortization of prior service (benefit) cost	0	0	1	1
Amortization of losses	0	0	0	0
Net periodic benefit (income) cost	(23)	(23)	(69)	(64)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	0	1	1	2
Interest cost	3	3	10	10
Expected return on plan assets	0	0	0	(1)
Amortization of prior service (benefit) cost	0	(1)	(2)	(2)
Amortization of losses	0	1	0	2
Net periodic benefit (income) cost	3	4	9	11
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(15)	(14)	(44)	(41)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ 2	$ 3	$ 7	$ 8