Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 499	$ 508
Derivatives:
Derivative assets	2,930	2,386
Derivatives:
Derivative liability	2,304	1,340
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	3,115	363
Special use funds:
Equity securities	3,166	3,963
U.S. Government and municipal bonds	671	717
Corporate debt securities	733	748
Mortgage-backed securities	505	517
Other debt securities	107	117
Other investments:
Equity Securities	41	46
Debt securities	144	151
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(3,467)	(2,700)
Derivative assets	2,900	2,350
Derivatives:
Derivative liability, netting	(3,393)	(2,625)
Derivative liability	710	576
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(30)	(17)
Derivative assets	9	9
Derivatives:
Derivative liability, netting	(30)	(17)
Derivative liability	1,487	725
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	0	1
Derivative assets	21	27
Derivatives:
Derivative liability, netting	0	1
Derivative liability	107	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	3,115	363
Special use funds:
Equity securities	1,505	1,875
U.S. Government and municipal bonds	503	567
Corporate debt securities	1	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	30	34
Debt securities	65	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	1,628	1,229
Derivatives:
Derivative Liability, Gross Liability	1,838	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	1,661	2,088
U.S. Government and municipal bonds	168	150
Corporate debt securities	732	748
Mortgage-backed securities	505	517
Other debt securities	107	117
Other investments:
Equity Securities	11	12
Debt securities	79	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	2,714	2,082
Derivatives:
Derivative Liability, Gross Liability	1,780	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	39	24
Derivatives:
Derivative Liability, Gross Liability	1,496	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	21	26
Derivatives:
Derivative Liability, Gross Liability	107	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	2,025	1,739
Derivatives:
Derivative Liability, Gross Liability	485	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	21	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	79	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	55	64
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	132	118
Derivatives:
Derivative assets	3	3
Derivatives:
Derivative liability	15	13
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	1,127	156
Special use funds:
Equity securities	1,989	2,491
U.S. Government and municipal bonds	508	535
Corporate debt securities	529	533
Mortgage-backed securities	375	395
Other debt securities	99	111
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2)	(1)
Derivative assets	3	3
Derivatives:
Derivative liability, netting	(2)	(1)
Derivative liability	15	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	1,127	156
Special use funds:
Equity securities	484	596
U.S. Government and municipal bonds	396	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	1,505	1,895
U.S. Government and municipal bonds	112	106
Corporate debt securities	529	533
Mortgage-backed securities	375	395
Other debt securities	99	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	3	3
Derivatives:
Derivative Liability, Gross Liability	6	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	11	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	77	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	$ 55	$ 64