Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 2,248	$ 1,971
Derivative Liability	1,689	1,428
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	815	712
Derivative Asset, Collateral, Obligation to Return Cash, Offset	261	279
Assets held for sale [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	42	57
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1,391	1,202
Derivative Asset, Collateral, Obligation to Return Cash, Offset	165	151
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	974	882
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	8	46
Liabilities associated with assets held-for-sale [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	16	16
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	699	530
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	14	13
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		1,937
Derivative Liability		982
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		34
Derivative Liability		319
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		0
Derivative Liability		127
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		33
Derivative Liability, Fair Value, Gross Liability		287
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	6,832	5,908
Derivative Liability, Fair Value, Gross Liability	5,869	4,740
Derivative Asset	2,248
Derivative Liability	1,689
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	7	4
Derivative Liability	257	222
FPL [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	3	3
FPL [Member] | Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	4	1
FPL [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	256	222
FPL [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	1
Commodity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		0
Derivative Liability, Fair Value, Gross Liability		0
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	6,772	5,906
Derivative Liability, Fair Value, Gross Liability	5,281	4,580
Derivative Asset	2,201
Derivative Liability	1,114
Commodity Contract [Member] | FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		4
Derivative Liability		222
Commodity Contract [Member] | FPL [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		0
Derivative Liability, Fair Value, Gross Liability		0
Commodity Contract [Member] | FPL [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	11	7
Derivative Liability, Fair Value, Gross Liability	261	225
Derivative Asset	7
Derivative Liability	257
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		33
Derivative Liability, Fair Value, Gross Liability		155
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	60	2
Derivative Liability, Fair Value, Gross Liability	490	160
Derivative Asset	47
Derivative Liability	486
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		0
Derivative Liability, Fair Value, Gross Liability		132
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	98	$ 0
Derivative Asset	0
Derivative Liability	$ 89