SHARE-BASED COMPENSATION Stock-Based Compensation - Restricted Liability Units (Details) (USD $)	12 Months Ended
Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Units Oustanding	165,870
Restricted Stock Units Outstanding Weighted Average Grant Date Fair Value	$ 20.68
Restricted Stock Units Granted	51,611
Restricted Stock Units Granted Weighted Average Grant Date Fair Value	$ 42.08
Restricted Stock Units Released	(87,509)
Restricted Stock Units Released Weighted Average Grant Date Fair Value	$ 18.47
Restricted Stock Units Forfeited	(4,918)
Restricted Stock Units Forfeited Weighted Average Grant Date Fair Value	$ 18.97
Restricted Stock Units Oustanding	125,054
Restricted Stock Units Outstanding Weighted Average Grant Date Fair Value	$ 31.15

The weighted average grant date fair value of restricted stock units vested during the period.

No definition available.

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Period Type:	duration

The number of restricted stock units forfeited during the period.

No definition available.

Name:	pepl_RestrictedStockUnitsForfeited
Namespace Prefix:	pepl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The weighted average grant date fair value of restricted stock units forfeited during the period.

No definition available.

Name:	pepl_Restrictedstockunitsforfeitedweightedaveragegrantdatefairvalue
Namespace Prefix:	pepl_
Data Type:	num:perShareItemType
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Period Type:	duration

The number of restricted stock units granted during the period.

No definition available.

Name:	pepl_RestrictedStockUnitsGranted
Namespace Prefix:	pepl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The weighted average grant date fair value of restricted stock granted during the period.

No definition available.

Name:	pepl_Restrictedstockunitsgrantedweightedaveragegrantdatefairvalue
Namespace Prefix:	pepl_
Data Type:	num:perShareItemType
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Period Type:	duration

The number of resticted stock units outstanding.

No definition available.

Name:	pepl_Restrictedstockunitsoustanding
Namespace Prefix:	pepl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The weighted average grant date fair value of restricted stock units outstanding.

No definition available.

Name:	pepl_Restrictedstockunitsoutstandingweightedaveragegrantdatefairvalue
Namespace Prefix:	pepl_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

The number of restricted stock units vested during the period.

No definition available.

Name:	pepl_RestrictedStockUnitsVested
Namespace Prefix:	pepl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration