Summary of Significant Accounting and Reporting Policies (Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current:
Storm reserve deficiency	$ 0	$ 203
Other	336	321
Total	336	524
Noncurrent:
Purchased power agreement termination	963	636
Other	1,506	1,258
Total	2,469	1,894
Current:
Derivatives	0	208
Deferred clause revenues	296	86
Other	50	5
Total	346	299
Noncurrent:
Accrued asset removal costs	601	1,956
Asset retirement obligation regulatory expense difference	2,569	2,294
Deferred Tax Liabilities, Net, Noncurrent	4,981	96
Other	614	560
Total	8,765	4,906
FPL[Member]
Current:
Storm reserve deficiency	0	203
Other	335	321
Total	335	524
Noncurrent:
Purchased power agreement termination	963	636
Other	1,286	937
Total	2,249	1,573
Current:
Derivatives	0	208
Deferred clause revenues	296	86
Other	37	0
Total	333	294
Noncurrent:
Accrued asset removal costs	585	1,944
Asset retirement obligation regulatory expense difference	2,569	2,294
Deferred Tax Liabilities, Net, Noncurrent	4,903	96
Other	585	559
Total	$ 8,642	$ 4,893