Financial Instruments (Available for Sale Securities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Realized gains	$ 252	$ 183	$ 106
Realized losses	67	88	30
Proceeds from sale and maturity of Available-for-sale Securities	5,028	4,348	6,726
Available For Sale Securities: Special Use Funds - Equity securities [Member]
Total unrealized gains on available for sale securities
Unrealized gains on available for sale securities	680	546
available for sale securities: Special Use Funds - Debt Securities [Member]
Total unrealized gains on available for sale securities
Unrealized gains on available for sale securities	92	107
FPL [Member]
Schedule of Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds [Line Items]
Realized gains	98	74	49
Realized losses	46	62	22
Proceeds from sale and maturity of Available-for-sale Securities	3,790	2,988	5,079
FPL [Member] | Available For Sale Securities: Special Use Funds - Equity securities [Member]
Total unrealized gains on available for sale securities
Unrealized gains on available for sale securities	521	376
FPL [Member] | available for sale securities: Special Use Funds - Debt Securities [Member]
Total unrealized gains on available for sale securities
Unrealized gains on available for sale securities	$ 77	$ 94