Leasing Activities (Income Recognized From Cross-border Energy Lease Investments) (Details) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Leasing Activities
Pre-tax income from PHI's cross-border energy lease investments (included in "Other Operating Revenue")	$ 7	$ 15	$ 35	$ 41
Income tax expense (benefit) related to cross-border energy lease investments	(3)	4	7	11
Net income from PHI's cross-border energy lease investments	$ 10	$ 11	$ 28	$ 30

The tax effect from the current year income from arrangements meeting the criteria for classification as a leveraged lease.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6792436&loc=d3e45152-112736

Name:	us-gaap_LeveragedLeasesIncomeStatementIncomeTaxExpenseOnLeveragedLeases
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration