Income Taxes (Tax Carryforwards and Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	$ 1,070		$ 1,343
Tax credit carryforwards	2,742		2,522
Federal [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	752
Tax credit carryforwards	2,409
State [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	169
Tax credit carryforwards	333	[1]
Tax credit carryforward with indefinite expiration period	149
Foreign [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	149	[2]
Operating loss carryforwards with indefinite expiration period	119
FPL [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	0		96
Tax credit carryforwards	$ 0		$ 0

[1] Includes $149 million of ITC carryforwards with an indefinite expiration period.

[2] Includes $119 million of net operating loss carryforwards with an indefinite expiration period.