Share Repurchase Authorization Share Repurchase Authorization (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended	36 Months Ended
Dec. 27, 2011	Dec. 28, 2010	Dec. 27, 2011
Payments for Repurchase of Equity [Abstract]
Stock Repurchase Program, Authorized Amount			$ 600.0
Stock Repurchase Program Shares Repurchased (in shares)	877,100	1,905,540	2,810,069
Stock Repurchase Program Average Cost Per Share (in dollars per share)	$ 103.55	$ 78.72	$ 86.33
Share Repurchase Program, shares repurchased	90.8	150.0	242.6
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 357.4

Share Repurchase Program, shares repurchased in dollars under the program.

No definition available.

Name:	pnra_ShareRepurchaseProgramSharesRepurchased
Namespace Prefix:	pnra_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

Represents the total cost of shares repurchased under a stock repurchase plan divided by the total number of shares repurchased.

No definition available.

Name:	pnra_StockRepurchaseProgramAverageCostPerShare
Namespace Prefix:	pnra_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Represents the number of shares repurchased during the period under a stock repurchase plan.

No definition available.

Name:	pnra_StockRepurchaseProgramSharesRepurchased
Namespace Prefix:	pnra_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_PaymentsForRepurchaseOfEquityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The remaining repurchase amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration