Summary of Significant Accounting and Reporting Policies (Goodwill and Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets [Line Items]
Goodwill	$ 4,204	$ 891
Other intangible assets not subject to amortization, primarily land easements	135	135
Other intangible assets:
Total	473	659
Accumulated amortization	(56)	(86)
Total other intangible assets subject to amortization - net	417	573
Intangible assets, amortization [Abstract]
Amortization expense	18	19	$ 35
Amortization Expense 2020	18
Amortization Expense 2021	14
Amortization Expense 2022	8
Amortization Expense 2023	7
Amortization Expense 2024	$ 4
Purchased Power Agreements [Member]
Other intangible assets:
Weighted average useful lives (years)	17 years
Total	$ 401	625
Other, primarily transmission and development rights and customer lists [Member]
Other intangible assets:
Weighted average useful lives (years)	22 years
Total	$ 72	34
Rate-Regulated Transmission [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	610	0
Gas Infrastructure, primarily Texas pipelines [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	487	487
Customer Supply [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	93	72
Generation Assets [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	28	28
Other Goodwill Assets [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	2,686	0
FPL[Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	300	302
FPL[Member] | Florida City Gas [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	291	293
FPL[Member] | Other Goodwill Assets [Member]
Goodwill and Intangible Assets [Line Items]
Goodwill	$ 9	$ 11