Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 22	$ 21	$ 45	$ 42
Interest cost	16	23	32	46
Expected return on plan assets	(85)	(80)	(170)	(161)
Amortization of prior service benefit	0	0	0	0
Amortization of actuarial loss	6	4	12	9
Special termination benefits	0	7	0	9
Net periodic benefit (income) cost	(41)	(25)	(81)	(55)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	0	0	1	1
Interest cost	1	2	2	3
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	(4)	(4)	(8)	(8)
Amortization of actuarial loss	2	1	3	2
Special termination benefits	0	0	0	0
Net periodic benefit (income) cost	(1)	(1)	(2)	(2)
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(27)	(21)	(54)	(42)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ (1)	$ (1)	$ (2)	$ (2)