Leasing Activities (Income Recognized From Cross-border Energy Lease Investments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Leasing Activities [Abstract]
Pre-tax income from PHI's cross-border energy lease investments (included in Other Revenue)	$ 55	$ 55	$ 54
Non-cash charge to reduce equity value of PHI's cross-border energy lease investments	(7)	(2)	(3)
Pre-tax income from PHI's cross-border energy lease investments after adjustment	48	53	51
Income tax expense	10	14	16
Net income from PHI's cross-border energy lease investments	$ 38	$ 39	$ 35

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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