Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2013
Accounting Policies [Abstract]
Fiscal Period Policy	The fiscal periods included herein comprise 13 weeks for the first-quarter periods.
Comparability of Prior Year Financial Data Policy	For comparability, certain prior-year amounts have been reclassified to conform with the 2013 Condensed Consolidated Balance Sheet presentation.
Marketable securities	Marketable securities We have investments in marketable debt and equity securities. We determine the appropriate classification of our investments at the date of purchase and reevaluate the classifications at the balance sheet date. Marketable debt securities with maturities of 12 months or less are classified as short-term. Marketable debt securities with maturities greater than 12 months are classified as long-term. We have the intent and ability to hold our marketable debt securities until maturity; therefore they are accounted for as held-to-maturity and stated at amortized cost. Our marketable equity security is accounted for as available-for-sale and stated at fair value. Changes in the fair value of our available-for-sale security are recognized as unrealized gains or losses, net of taxes, as a component of accumulated other comprehensive income/(loss).

Disclosure of accounting policy for determining an entity's fiscal year or other fiscal period. This disclosure may include identification of the fiscal period end-date, the length of the fiscal period, any reporting period lag between the entity and its subsidiaries, or equity investees. If a reporting lag exists, the closing date of the entity having a different period end is generally noted, along with an explanation of the necessity for using different closing dates. Any intervening events that materially affect the entity's financial position or results of operations are generally also disclosed.

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- Definition

Disclosure of accounting policy for investments in debt and equity securities that have readily determinable fair values (marketable securities). At a minimum, the disclosure might address accounting policies for investments classified as trading, available for sale, or held to maturity and may include how the entity determines whether impairments of available for sale or held to maturity investments are other than temporary, how the fair values of the entity's securities are determined, and the entity's accounting treatment for transfers between investment categories.

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-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.

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-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.

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