Goodwill and Other Intangible Assets (Other Intangibles-Aquired) (Details) (WPD Midlands [Member], Easements [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
WPD Midlands [Member] \| Easements [Member]
Acquired indefinite-lived intangible assets: [Line Items]
Gross carrying amount	$ 88	$ 88

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, resulting from a business combination.

No definition available.

Name:	us-gaap_IndefinitelivedIntangibleAssetsAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration