Non-Derivative Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 312	$ 441
Derivatives:
Derivative assets	2,337	2,217
Derivatives:
Derivative liability	4,135	1,510
NEER Segment
Derivatives:
Contingent consideration liabilities	265
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	150	742
Special use funds:
Equity securities	5,294	4,726
U.S. Government and municipal bonds	882	717
Corporate debt securities	863	871
Mortgage-backed securities	439	422
Other debt securities	144	124
Other investments:
Equity Securities	67	62
Debt securities	321	218
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(10,589)	(2,325)
Derivative assets	2,255	2,154
Derivatives:
Derivative liability, netting	(10,238)	(2,277)
Derivative liability	3,422	500
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(38)	(41)
Derivative assets	87	40
Derivatives:
Derivative liability, netting	(38)	(41)
Derivative liability	662	1,001
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	(17)	(34)
Derivative assets	(5)	23
Derivatives:
Derivative liability, netting	(17)	(34)
Derivative liability	51	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	150	742
Special use funds:
Equity securities	2,445	2,237
U.S. Government and municipal bonds	816	590
Corporate debt securities	1	1
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	66	62
Debt securities	125	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	4,155	919
Derivatives:
Derivative Liability, Gross Liability	4,609	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	2,849	2,489
U.S. Government and municipal bonds	66	127
Corporate debt securities	862	870
Mortgage-backed securities	439	422
Other debt securities	144	124
Other investments:
Equity Securities	1	0
Debt securities	173	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	6,856	1,881
Derivatives:
Derivative Liability, Gross Liability	6,770	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	125	81
Derivatives:
Derivative Liability, Gross Liability	700	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	12	57
Derivatives:
Derivative Liability, Gross Liability	68	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	23	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,833	1,679
Derivatives:
Derivative Liability, Gross Liability	2,281	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	68	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		42
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	68	135
Derivatives:
Derivative liability	8	3
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	81	137
Special use funds:
Equity securities	3,427	3,012
U.S. Government and municipal bonds	701	536
Corporate debt securities	640	627
Mortgage-backed securities	314	335
Other debt securities	129	119
Other investments:
Equity Securities	13	12
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(7)	0
Derivative assets	16	3
Derivatives:
Derivative liability, netting	(7)	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	81	137
Special use funds:
Equity securities	833	752
U.S. Government and municipal bonds	652	449
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	13	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	2,594	2,260
U.S. Government and municipal bonds	49	87
Corporate debt securities	640	627
Mortgage-backed securities	314	335
Other debt securities	129	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	14	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	9	2
Derivatives:
Derivative Liability, Gross Liability	10	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	$ 67	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		$ 42