Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 20	$ 18	$ 60	$ 52
Interest cost	28	20	86	62
Expected return on plan assets	(78)	(69)	(235)	(207)
Amortization of prior service benefit	0	0	(1)	(1)
Special termination benefits	1	14	17	14
Net periodic benefit (income) cost	(29)	(17)	(73)	(80)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	0	0	1	1
Interest cost	3	2	7	5
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	(4)	(4)	(12)	(12)
Special termination benefits	0	0	0	0
Net periodic benefit (income) cost	(1)	(2)	(4)	(6)
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(18)	(11)	(53)	(51)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ (1)	$ (2)	$ (3)	$ (4)