Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Federal:
Current	$ (35)	[1]	$ 11	[1]	$ (18)	[1]
Deferred	572		434		290
Total federal	537		445		272
State:
Current	11	[1]	11	[1]	77	[1]
Deferred	(19)		76		(22)
Total state	(8)		87		55
Total income taxes	529		532		327
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Statutory federal income tax rate (in hundredths)	35.00%		35.00%		35.00%
Increases (reductions) resulting from:
State income taxes - net of federal income tax benefit (in hundredths)	(0.20%)		2.40%		1.90%
PTCs and ITCs - NEER (in hundredths)	(11.10%)		(12.20%)		(13.10%)
Convertible ITCs - NEER (in hundredths)	(0.10%)		(2.50%)		(4.30%)
Other - net (in hundredths)	(2.00%)		(1.30%)		(2.60%)
Effective income tax rate (in hundredths)	21.60%		21.40%		16.90%
Deferred tax liabilities:
Property-related	8,727		7,795
Pension	394		485
Storm reserve deficiency	235		258
Nuclear decommissioning trusts	117		146
Net unrealized gains on derivatives	209		226
Deferred fuel costs	40		101
Other	573		638
Total deferred tax liabilities	10,295		9,649
Deferred tax assets and valuation allowance:
Decommissioning reserves	406		393
Postretirement benefits	170		175
Net operating loss carryforwards	557		663
Tax credit carryforwards	2,111		1,819
ARO and accrued asset removal costs	884		895
Other	830		790
Valuation allowance	(228)	[2]	(246)	[2]
Net deferred tax assets	4,730		4,489
Net accumulated deferred income taxes	(5,565)		(5,160)
Deferred tax assets and liabilities included in the consolidated balance sheets [Abstract]
Other current assets	10		17
Other assets	153		106
Other current liabilities	(47)		(174)
Accumulated deferred income taxes	(5,681)		(5,109)
Net accumulated deferred income taxes	$ (5,565)		$ (5,160)

[1] Includes provision for unrecognized tax benefits.

[2] Amount relates to deferred state tax credits and state operating loss carryforwards.