Income Taxes (Tax Carryforwards and Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended					12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2012 Federal [Member]	Dec. 31, 2012 State [Member]	Dec. 31, 2012 Federal [Member]	Dec. 31, 2012 State [Member]	Dec. 31, 2012 Foreign [Member]	Dec. 31, 2012 FPL [Member]	Dec. 31, 2011 FPL [Member]	Dec. 31, 2010 FPL [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
federal operating loss carryforward expected		$ 430
Net operating loss carryforwards	557	1,216				1,057	137	22	6	0
Expiration dates						2026-2032	2013-2032	2021-2032
Tax credit carryforwards	2,111	2,312		2,019	293				0	0
Years under examination						2011
Liabilities for unrecognized tax benefits			264								215
Cash refund from tax settlement	278
Tax settlement, interest	$ 131