Acquisitions Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014	Feb. 02, 2015	Jan. 03, 2015
Business Acquisition [Line Items]
Goodwill	$ 766,046		$ 766,046			$ 320,538
Goodwill, Acquired During Period			449,023
Goodwill, Translation Adjustments			$ (3,515)
Siemens Health Services [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition			Feb. 02, 2015
Business Acquisition, Name of Acquired Entity			Siemens Health Services
Business Acquisition, Description of Acquired Entity			Siemens Health Services offered a portfolio of enterprise-level clinical and financial health care information technology solutions, as well as departmental, connectivity, population health, and care coordination solutions globally. Solutions were offered on the Soarian®, Invision®, and i.s.h.med® platforms, among others. Siemens Health Services also offered a range of complementary services including support, hosting, managed services, implementation services, and strategic consulting.
Business Combination, Reason for Business Combination			We believe the acquisition enhances our organic growth opportunities as it provides us a larger base into which we can sell our combined portfolio of solutions and services. The acquisition also augments our non-U.S. footprint and growth opportunities, increases our scale for R&D investment, and adds over 5,000 highly-skilled associates that will enhance our capabilities.
Business Combination, Goodwill Recognized, Description			These factors, combined with the synergies and economies of scale expected from combining the operations of Cerner and Siemens Health Services, are the basis for the acquisition and comprise the resulting goodwill recorded.
Business Combination, Consideration Transferred			$ 1,370,000
Business Combination, Base Purchase Price			$ 1,300,000
Business Acquisition, Date of Acquisition Agreement			Aug. 05, 2014
Business Acquisition, Transaction Costs	20,000		$ 20,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Reasons			The allocation of purchase price is preliminary and subject to changes, which could be significant, as appraisals of tangible and intangible assets are finalized, working capital and pension obligation adjustments are agreed upon and finalized, and additional information becomes available.
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables					$ 236,491
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other					56,859
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment					158,298
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, PP&E, Weighted Average Useful Life			20 years
Goodwill					449,023
Intangible assets					637,980
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets					233
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable					(42,076)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue					(90,148)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other					(19,716)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Deferred Revenue					(14,930)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net					1,372,014
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	260,000		$ 435,000
Business Combination, Pro Forma Information, Disclosure Impracticable			Disclosure of the earnings contribution from the Cerner Health Services business is not practicable, as we have already integrated operations in many areas.
Business Acquisition, Pro Forma Revenue	1,125,997	$ 1,144,861	$ 2,215,766	$ 2,210,662
Business Acquisition, Pro Forma Net Income (Loss)	$ 117,047	$ 115,043	$ 231,379	$ 213,132
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 0.33	$ 0.33	$ 0.66	$ 0.61
Business Acquisition, Pro Forma Information, Description			These pro forma results are based on estimates and assumptions, which we believe are reasonable. They are not the results that would have been realized had we been a combined company during the periods presented, nor are they indicative of our consolidated results of operations in future periods.
Business Acquisition, Goodwill, Expected Tax Deductible Amount					449,023
Business Combination, Acquired Receivables, Estimated Uncollectible					33,674
Customer Relationships [Member] | Siemens Health Services [Member]
Business Acquisition [Line Items]
Intangible assets					396,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			10 years
Developed Technology Rights [Member] | Siemens Health Services [Member]
Business Acquisition [Line Items]
Intangible assets					201,990
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years
Trade Names [Member] | Siemens Health Services [Member]
Business Acquisition [Line Items]
Intangible assets					$ 39,990
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			8 years
Domestic Segment | Siemens Health Services [Member]
Business Acquisition [Line Items]
Goodwill	$ 697,833		$ 697,833			311,170
Goodwill, Acquired During Period			386,663
Goodwill, Translation Adjustments			0
Global Segment | Siemens Health Services [Member]
Business Acquisition [Line Items]
Goodwill	68,213		68,213			$ 9,368
Goodwill, Acquired During Period			62,360
Goodwill, Translation Adjustments			(3,515)
Acquired Intangible Amortization [Member] | Siemens Health Services [Member]
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)		$ 22,000	7,000	$ 43,000
Fair Value Adjustment to Deferred Revenue [Member] | Siemens Health Services [Member]
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)		$ 7,000	6,000	$ 25,000
Acquisition-related Costs [Member] | Siemens Health Services [Member]
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	$ 3,000		$ 20,000