Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Current	$ 570	$ 762
Derivative Asset, Noncurrent	1,647	1,624
Derivative Assets	2,217	2,386
Derivative Liability, Current	311	344
Derivative Liability, Noncurrent	1,199	863
Derivative Liabilities	1,510	1,340
Current derivative assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Margin cash collateral received from counterparties		2
Non Current Derivative Assets Member [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Margin cash collateral received from counterparties	184	139
Other Current Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Current other liabilities		133
Current derivative liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Margin cash collateral paid to counterparties	136	66
Commodity contracts [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Assets	2,154	2,350
Derivative Liabilities	500	576
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(2,325)	(2,700)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(2,277)	(2,625)
Commodity contracts [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	919	1,229
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	1,004	1,365
Commodity contracts [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	1,881	2,082
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	1,468	1,446
Commodity contracts [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	1,679	1,739
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	305	390
Interest Rate Contract [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Assets	40	9
Derivative Liabilities	1,001	725
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(41)	(17)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(41)	(17)
Interest Rate Contract [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Interest Rate Contract [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	81	24
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	1,042	598
Interest Rate Contract [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	2
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	144
Currency Swap [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Assets	23	27
Derivative Liabilities	9	39
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(34)	1
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(34)	1
Currency Swap [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Currency Swap [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	57	26
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	43	38
Currency Swap [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
FPL[Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Liabilities	3	13
FPL[Member] \| Current other assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Current	3	3
FPL[Member] \| Other Current Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Liability, Current	2	12
FPL[Member] \| Other Noncurrent Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Liability, Noncurrent	1
Derivative Liabilities		1
FPL[Member] \| Commodity contracts [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Assets	3	3
Derivative Liabilities	3	13
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	0	(1)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	0	(1)
FPL[Member] \| Commodity contracts [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
FPL[Member] \| Commodity contracts [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	1	3
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	5
FPL[Member] \| Commodity contracts [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Recurring [Member]
Derivative Instruments and Hedging Activities Disclosures [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	2	1
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ 3	$ 9

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