1.0.0.3 false CONSOLIDATED STATEMENTS of COMPREHENSIVE INCOME (USD $) In Millions false 1 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 5 Net income 3 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 761000000 761 false false 2 true true 836000000 836 false false 3 true true 496000000 496 false false No definition available. No authoritative reference available. false 6 Reclassification adjustments included in net income 3 pgn_ReclassificationAdjustmentsIncludedInNetIncome pgn false na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false No definition available. false 7 Change in cash flow hedges (net of tax expense of $4, $2 and $3, respectively) 4 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 6000000 6 false false 2 false true 3000000 3 false false 3 false true 4000000 4 false false No definition available. No authoritative reference available. false 8 Change in unrecognized items for pension and other postretirement benefits (net of tax expense of $3, $1 and $1, respectively) 4 pgn_OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossNetTransitionAssetObligationAndPriorServiceCostRecognizedInNetPeriodicBenefitCostNetOfTax pgn false debit duration monetary The adjustment out of other comprehensive income for the net (gain) loss, net transition asset (obligation) and prior service... false false false false false false false false false 1 false true 4000000 4 false false 2 false true 1000000 1 false false 3 false true 2000000 2 false false The adjustment out of other comprehensive income for the net (gain) loss, net transition asset (obligation) and prior service cost recognized as a component of net periodic benefit cost during the period, after tax. No authoritative reference available. false 9 Net unrealized gains (losses) on cash flow hedges (net of tax (expense) benefit of $(10), $24 and $8, respectively) 3 us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 16000000 16 false false 2 false true -37000000 -37 false false 3 false true -13000000 -13 false false No definition available. No authoritative reference available. false 10 Net unrecognized items on pension and other postretirement benefits (net of tax (expense) benefit of $(1), $29 and $(16), respectively) 3 us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2000000 2 false false 2 false true -49000000 -49 false false 3 false true 23000000 23 false false No definition available. No authoritative reference available. false 11 Other (net of tax benefit of $0, $1 and $3, respectively) 3 pgn_OtherComprehensiveIncomeOtherNetOfTax pgn false credit duration monetary The total net of tax amount of other comprehensive income, not previously categorized due to materiality considerations. false false false false false false false false false 1 false true 1000000 1 false false 2 false true 0 0 false false 3 false true -1000000 -1 false false The total net of tax amount of other comprehensive income, not previously categorized due to materiality considerations. No authoritative reference available. false 12 Other comprehensive income (loss) 3 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 29000000 29 false false 2 false true -82000000 -82 false false 3 false true 15000000 15 false false No definition available. No authoritative reference available. true 13 Comprehensive income 3 us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 790000000 790 false false 2 false true 754000000 754 false false 3 false true 511000000 511 false false No definition available. No authoritative reference available. true 14 Comprehensive (income) loss attributable to noncontrolling interests, net of tax 3 us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -4000000 -4 false false 2 false true -6000000 -6 false false 3 false true 8000000 8 false false No definition available. No authoritative reference available. false 15 Comprehensive income attributable to controlling interests 3 us-gaap_ComprehensiveIncomeNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 786000000 786 false false 2 true true 748000000 748 false false 3 true true 519000000 519 false false No definition available. No authoritative reference available. false false 3 11 false Millions UnKnown UnKnown false true