Contingencies Contingencies (Narrative) (Details)	12 Months Ended
Dec. 31, 2020
Fujitsu [Member]
Loss Contingencies [Line Items]
Loss Contingency, Management's Assessment and Process	As previously disclosed, we were in dispute with Fujitsu Services Limited ("Fujitsu") regarding Fujitsu's obligation to pay amounts to us due upon the termination of a subcontract, including client receivables, in connection with Fujitsu's contract as the prime contractor in the National Health Service ("NHS") initiative to automate clinical processes and digitize medical records in the Southern region of England. The NHS terminated its contract with Fujitsu, which gave rise to the termination of our subcontract with Fujitsu. We filed a request for arbitration with the London Court of International Arbitration on April 22, 2019 seeking damages. On December 30, 2019, Fujitsu filed its Defense and Counterclaim (the "Counterclaim") in response. In its Counterclaim, Fujitsu defended against our claim in full and argued that we are liable to Fujitsu for: (i) £306 million in damages based on our alleged fraudulent misrepresentations inducing Fujitsu to enter into the subcontract; or (ii) alternatively, £173.8 million in damages based on our alleged breaches of the subcontract. The parties entered into a settlement on November 2, 2020, agreeing to dismiss all claims against each other with prejudice.
NextGen [Member]
Loss Contingencies [Line Items]
Loss Contingency, Management's Assessment and Process	Cerner Health Services, Inc. ("Cerner HS"), a wholly owned subsidiary of Cerner Corporation, filed a lawsuit in the Chester County, Pennsylvania, Court of Common Pleas against NextGen Healthcare Information Systems, LLC ("NextGen") relating to a dispute arising out of a supplier relationship initially established between Siemens Health Services, Inc. and NextGen prior to the acquisition of the assets of Siemens Health Services, Inc. by Cerner HS in 2015. In September 2017, the court issued a preliminary injunction to prevent NextGen from refusing to honor certain contractual obligations to support Cerner HS's clients who use NextGen ambulatory EHR solutions. In September 2018, NextGen filed a counterclaim alleging breach of contract and tortious interference but did not specify its damages. NextGen has provided an expert report alleging profit disgorgement damages of $122 million or, alternatively, $26 million in lost profit damages. In December 2019, we deposed NextGen's expert, gaining additional clarity on categories of alleged damages but not on the alleged theories of liability. A trial commenced on January 25, 2021. We believe NextGen's claims are without merit and are vigorously defending against them; however, there can be no assurances as to the outcome of the dispute. We have not concluded that a loss related to the claims raised by NextGen in its counterclaim is probable, nor have we accrued a liability related to these claims. Although a loss may be reasonably possible (as defined in ASC 450), we do not have sufficient information to determine the amount or range of reasonably possible loss in light of the inherent difficulty of predicting the outcome of litigation generally, the wide range of damages presented by NextGen's expert, and the continued lack of clarity on the causal connection between Cerner Corporation's and Cerner HS's actions and any alleged damages.

Contingencies Contingencies (Narrative) (Details)

12 Months Ended

Dec. 31, 2020

Loss Contingency, Management's Assessment and Process

As previously disclosed, we were in dispute with Fujitsu Services Limited ("Fujitsu") regarding Fujitsu's obligation to pay amounts to us due upon the termination of a subcontract, including client receivables, in connection with Fujitsu's contract as the prime contractor in the National Health Service ("NHS") initiative to automate clinical processes and digitize medical records in the Southern region of England. The NHS terminated its contract with Fujitsu, which gave rise to the termination of our subcontract with Fujitsu. We filed a request for arbitration with the London Court of International Arbitration on April 22, 2019 seeking damages. On December 30, 2019, Fujitsu filed its Defense and Counterclaim (the "Counterclaim") in response. In its Counterclaim, Fujitsu defended against our claim in full and argued that we are liable to Fujitsu for: (i) £306 million in damages based on our alleged fraudulent misrepresentations inducing Fujitsu to enter into the subcontract; or (ii) alternatively, £173.8 million in damages based on our alleged breaches of the subcontract. The parties entered into a settlement on November 2, 2020, agreeing to dismiss all claims against each other with prejudice.

NextGen [Member]

Loss Contingencies [Line Items]

Loss Contingency, Management's Assessment and Process

Cerner Health Services, Inc. ("Cerner HS"), a wholly owned subsidiary of Cerner Corporation, filed a lawsuit in the Chester County, Pennsylvania, Court of Common Pleas against NextGen Healthcare Information Systems, LLC ("NextGen") relating to a dispute arising out of a supplier relationship initially established between Siemens Health Services, Inc. and NextGen prior to the acquisition of the assets of Siemens Health Services, Inc. by Cerner HS in 2015. In September 2017, the court issued a preliminary injunction to prevent NextGen from refusing to honor certain contractual obligations to support Cerner HS's clients who use NextGen ambulatory EHR solutions. In September 2018, NextGen filed a counterclaim alleging breach of contract and tortious interference but did not specify its damages. NextGen has provided an expert report alleging profit disgorgement damages of $122 million or, alternatively, $26 million in lost profit damages. In December 2019, we deposed NextGen's expert, gaining additional clarity on categories of alleged damages but not on the alleged theories of liability. A trial commenced on January 25, 2021. We believe NextGen's claims are without merit and are vigorously defending against them; however, there can be no assurances as to the outcome of the dispute. We have not concluded that a loss related to the claims raised by NextGen in its counterclaim is probable, nor have we accrued a liability related to these claims. Although a loss may be reasonably possible (as defined in ASC 450), we do not have sufficient information to determine the amount or range of reasonably possible loss in light of the inherent difficulty of predicting the outcome of litigation generally, the wide range of damages presented by NextGen's expert, and the continued lack of clarity on the causal connection between Cerner Corporation's and Cerner HS's actions and any alleged damages.