Revenue from Contract with Customer Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2020	Dec. 28, 2019	Dec. 29, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 1,395,025	$ 1,368,673	$ 1,330,349	$ 1,411,741	$ 1,442,232	$ 1,429,428	$ 1,431,061	$ 1,389,877	$ 5,505,788	$ 5,692,598	$ 5,366,325
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue									5,142,674	5,166,125	4,841,714
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue									363,114	526,473	524,611
Revenue, Licensed Software, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									656,219	680,585	613,578
Revenue, Technology Resale, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									196,591	246,885	245,076
Revenue, Subscriptions, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									378,208	358,715	325,709
Revenue, Professional Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,930,445	1,992,478	1,811,463
Revenue, Managed Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,245,427	1,213,900	1,154,941
Revenue, Support and Maintenance Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,070,779	1,104,638	1,118,116
Revenue, Reimbursement Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue									28,119	95,397	97,442
Domestic Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue									4,879,769	5,038,127	4,730,266
Domestic Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue									4,557,358	4,565,172	4,271,934
Domestic Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue									322,411	472,955	458,332
Domestic Segment [Member] | Revenue, Licensed Software, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									604,707	628,958	573,034
Domestic Segment [Member] | Revenue, Technology Resale, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									173,264	225,076	208,722
Domestic Segment [Member] | Revenue, Subscriptions, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									354,023	333,298	300,555
Domestic Segment [Member] | Revenue, Professional Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,717,873	1,760,532	1,574,407
Domestic Segment [Member] | Revenue, Managed Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,120,939	1,098,695	1,060,081
Domestic Segment [Member] | Revenue, Support and Maintenance Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									881,778	904,204	921,336
Domestic Segment [Member] | Revenue, Reimbursement Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue									27,185	87,364	92,131
International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue									626,019	654,471	636,059
International Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue									585,316	600,953	569,780
International Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue									40,703	53,518	66,279
International Segment [Member] | Revenue, Licensed Software, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									51,512	51,627	40,544
International Segment [Member] | Revenue, Technology Resale, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									23,327	21,809	36,354
International Segment [Member] | Revenue, Subscriptions, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									24,185	25,417	25,154
International Segment [Member] | Revenue, Professional Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									212,572	231,946	237,056
International Segment [Member] | Revenue, Managed Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									124,488	115,205	94,860
International Segment [Member] | Revenue, Support and Maintenance Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue									189,001	200,434	196,780
International Segment [Member] | Revenue, Reimbursement Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue									$ 934	$ 8,033	$ 5,311