Non-Derivative Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 703	$ 441
Derivatives:
Derivative assets	2,114	2,217
Derivatives:
Derivative liability	1,032	1,510
NEER Segment
Derivatives:
Contingent consideration liabilities	264
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	699	742
Special use funds:
Equity securities	4,979	4,726
U.S. Government and municipal bonds	775	717
Corporate debt securities	830	871
Mortgage-backed securities	434	422
Other debt securities	139	124
Other investments:
Equity Securities	70	62
Debt securities	239	218
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2,197)	(2,325)
Derivative assets	1,970	2,154
Derivatives:
Derivative liability, netting	(2,176)	(2,277)
Derivative liability	663	500
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(69)	(41)
Derivative assets	149	40
Derivatives:
Derivative liability, netting	(69)	(41)
Derivative liability	349	1,001
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	(40)	(34)
Derivative assets	(5)	23
Derivatives:
Derivative liability, netting	(40)	(34)
Derivative liability	20	9
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	699	742
Special use funds:
Equity securities	2,329	2,237
U.S. Government and municipal bonds	712	590
Corporate debt securities	1	1
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	70	62
Debt securities	104	91
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	775	919
Derivatives:
Derivative Liability, Gross Liability	858	1,004
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	2,650	2,489
U.S. Government and municipal bonds	63	127
Corporate debt securities	829	870
Mortgage-backed securities	434	422
Other debt securities	139	124
Other investments:
Equity Securities	0	0
Debt securities	120	127
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,893	1,881
Derivatives:
Derivative Liability, Gross Liability	1,639	1,468
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	218	81
Derivatives:
Derivative Liability, Gross Liability	418	1,042
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative Asset, Gross Asset	35	57
Derivatives:
Derivative Liability, Gross Liability	60	43
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	0	0
U.S. Government and municipal bonds	0	0
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	0	0
Debt securities	15	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,499	1,679
Derivatives:
Derivative Liability, Gross Liability	342	305
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Other Current Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	85	111
Other Noncurrent Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	9	42
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	94	135
Derivatives:
Derivative liability		3
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	97	137
Special use funds:
Equity securities	3,196	3,012
U.S. Government and municipal bonds	605	536
Corporate debt securities	618	627
Mortgage-backed securities	328	335
Other debt securities	126	119
Other investments:
Equity Securities	12	12
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(1)	0
Derivative assets	2	3
Derivatives:
Derivative liability, netting	(1)	0
Derivative liability	8	3
FPL [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	97	137
Special use funds:
Equity securities	791	752
U.S. Government and municipal bonds	558	449
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	12	12
FPL [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
FPL [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	2,405	2,260
U.S. Government and municipal bonds	47	87
Corporate debt securities	618	627
Mortgage-backed securities	328	335
Other debt securities	126	119
Other investments:
Equity Securities	0	0
FPL [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1	1
Derivatives:
Derivative Liability, Gross Liability	5	0
FPL [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	0	0
U.S. Government and municipal bonds	0	0
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	0	0
FPL [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	2	2
Derivatives:
Derivative Liability, Gross Liability	4	3
FPL [Member] | Other Current Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	84	91
FPL [Member] | Other Noncurrent Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 9	$ 42