Fair Value Measurements (Financial Assets Measured At Fair Value) (Details) (USD $) In Thousands	Jul. 02, 2011	Jan. 01, 2011
Level 1 [Member] \| Money Market Funds [Member]
Cash equivalents	$ 48,060	$ 44,237
Level 2 [Member] \| Time Deposits [Member]
Cash equivalents	6,686
Short-term investments	56,591	41,764
Level 2 [Member] \| Commercial Paper [Member]
Short-term investments	44,800	44,500
Level 2 [Member] \| Government and Corporate Bonds [Member]
Short-term investments	366,575	251,787
Long-term investments	329,990	264,467
Level 2 [Member] \| Auction Rate Securities [Member]
Short-term investments		$ 18,450

Fair value measured on recurring basis long term investments.

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Namespace Prefix:	cern
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents a certain statement of financial position asset caption which represents a class of assets, or which may include an individual asset, measured at fair value on a recurring basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph a

+ Details

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisCashAndCashEquivalents
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph a

+ Details

Name:	us-gaap_FairValueMeasuredOnRecurringBasisInvestments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant