Acquisitions Acquisitions (Details) (USD $)	9 Months Ended		9 Months Ended
	Sep. 27, 2014	Dec. 28, 2013	Sep. 27, 2014 Siemens [Member]	Sep. 27, 2014 InterMedHx [Member]	Apr. 01, 2014 InterMedHx [Member]
Business Acquisition [Line Items]
Pending Acquisition			Siemens Health Services
Pending Acquisition - Description	On August 5, 2014, we entered into a Master Sale and Purchase Agreement (the "Agreement") with Siemens AG, a stock corporation under the laws of Germany ("Siemens"), pursuant to which Cerner will acquire substantially all of the assets, and assume certain liabilities of Siemens' health information technology business unit, Siemens Health Services.
Pending Acquisition - Consideration	Consideration for this acquisition is expected to total $1.3 billion in cash, subject to certain adjustments for working capital and pension obligations. We expect to enter into a transition services agreement pursuant to which Siemens will provide certain transitional services to Cerner for an initial period of up to six months after the acquisition closing.
Business Acquisition, Goodwill, Expected Tax Deductible Amount					$ 16,800,000
Intangible assets					3,800,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				5 years
Business Acquisition, Effective Date of Acquisition				Apr. 01, 2014
Business Acquisition, Name of Acquired Entity				InterMedHx, LLC (InterMedHx)
Business Acquisition, Transaction Costs			9,400,000
Business Acquisition, Percentage of Voting Interests Acquired					100.00%
Business Acquisition, Description of Acquired Entity				InterMedHx is a provider of health technology solutions in the areas of preventive care, patient administration, and medication history.
Business Combination, Reason for Business Combination				We believe the addition of InterMedHx solutions provides additional capabilities in the market.
Business Combination, Consideration Transferred				19,100,000
Business Combination, Contingent Consideration, Liability					11,600,000
Goodwill	$ 322,135,000	$ 307,422,000			$ 16,800,000
Business Combination, Contingent Consideration Arrangements, Description				which is payable at a percentage of the revenue contribution from InterMedHx solutions and services