Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 17	$ 15	$ 33	$ 31
Interest cost	21	26	42	52
Expected return on plan assets	(68)	(65)	(135)	(130)
Amortization of prior service cost (benefit)	(1)	1	(1)	1
Special termination benefits	37	0	38	0
Postretirement benefits settlement	0	0	0	0
Net periodic benefit (income) cost	6	(23)	(23)	(46)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	1	0	1	1
Interest cost	2	4	4	7
Expected return on plan assets	0	0	0	0
Amortization of prior service cost (benefit)	(2)	(1)	(2)	(2)
Special termination benefits	0	0	0	0
Postretirement benefits settlement	1	0	1	0
Net periodic benefit (income) cost	2	3	4	6
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	6	(14)	(12)	(29)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ 1	$ 3	$ 3	$ 5