Derivatives and Hedging (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2012
Derivative [Line Items]
Pretax deferred losses related to effective cash flow hedges	$ 65	$ 144
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	6
Undesignated commodity contracts latest expiration year	2018
Progress Energy [Member]
Derivative [Line Items]
Pretax deferred losses related to effective cash flow hedges	$ 60	$ 68

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994

Name:	us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant