Employee Retirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 18	$ 16
Interest cost	24	25
Expected return on plan assets	(60)	(60)
Amortization of transition obligation	0	0
Amortization of prior service cost (benefit)	2	1
Amortization of Gains (Losses)	1	0
Net periodic benefit (income) cost	(15)	(18)
Other Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	1	1
Interest cost	4	5
Expected return on plan assets	0	0
Amortization of transition obligation	0	1
Amortization of prior service cost (benefit)	(1)	0
Amortization of Gains (Losses)	1	0
Net periodic benefit (income) cost	5	7
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(10)	(11)
FPL [Member] | Other Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ 3	$ 5