Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 476	$ 508
Derivatives:
Derivative assets	2,063	2,386
Derivatives:
Derivative liability	1,890	1,340
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	1,804	363
Special use funds:
Equity securities	4,181	3,963
U.S. Government and municipal bonds	679	717
Corporate debt securities	851	748
Mortgage-backed securities	440	517
Other debt securities	112	117
Other investments:
Equity Securities	61	46
Debt securities	202	151
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2,396)	(2,700)
Derivative assets	2,039	2,350
Derivatives:
Derivative liability, netting	(2,252)	(2,625)
Derivative liability	543	576
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(28)	(17)
Derivative assets	5	9
Derivatives:
Derivative liability, netting	(28)	(17)
Derivative liability	1,296	725
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	4	1
Derivative assets	19	27
Derivatives:
Derivative liability, netting	4	1
Derivative liability	51	39
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	1,804	363
Special use funds:
Equity securities	1,994	1,875
U.S. Government and municipal bonds	522	567
Corporate debt securities	1	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	61	34
Debt securities	93	82
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	1,029	1,229
Derivatives:
Derivative Liability, Gross Liability	1,027	1,365
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	2,187	2,088
U.S. Government and municipal bonds	157	150
Corporate debt securities	850	748
Mortgage-backed securities	440	517
Other debt securities	112	117
Other investments:
Equity Securities	0	12
Debt securities	109	69
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,796	2,082
Derivatives:
Derivative Liability, Gross Liability	1,328	1,446
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	33	24
Derivatives:
Derivative Liability, Gross Liability	1,304	598
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	15	26
Derivatives:
Derivative Liability, Gross Liability	47	38
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	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,610	1,739
Derivatives:
Derivative Liability, Gross Liability	440	390
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	2
Derivatives:
Derivative Liability, Gross Liability	20	144
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	231	60
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	82	64
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	114	118
Derivatives:
Derivative assets	2	3
Derivatives:
Derivative liability	11	13
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	191	156
Special use funds:
Equity securities	2,663	2,491
U.S. Government and municipal bonds	508	535
Corporate debt securities	600	533
Mortgage-backed securities	348	395
Other debt securities	107	111
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2)	(1)
Derivative assets	2	3
Derivatives:
Derivative liability, netting	(2)	(1)
Derivative liability	11	13
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	191	156
Special use funds:
Equity securities	680	596
U.S. Government and municipal bonds	405	429
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
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	1,983	1,895
U.S. Government and municipal bonds	103	106
Corporate debt securities	600	533
Mortgage-backed securities	348	395
Other debt securities	107	111
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	2	3
Derivatives:
Derivative Liability, Gross Liability	5	5
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
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	1
Derivatives:
Derivative Liability, Gross Liability	8	9
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	73	54
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	$ 41	$ 64