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Debt (Schedule Of Components Of Debt) (Details) - USD ($) $ in Millions	Apr. 02, 2021	Sep. 15, 2020	May 26, 2020	Apr. 03, 2020	Mar. 05, 2020	Feb. 04, 2020	Nov. 11, 2019	Feb. 09, 2017
Debt Instrument [Line Items]
Debt, gross	$ 3,620			$ 4,250
Less: unamortized discount and issuance costs	(19)			(29)
Total debt	3,601			4,221
Less: current portion	(313)			(756)
Total long-term portion	3,288			$ 3,465
2.00% Convertible Unsecured Notes due August 15, 2022 \| Convertible Debt
Debt Instrument [Line Items]
Stated interest rate (as a percent)				2.00%
Debt, gross	$ 0			$ 625
Effective interest rate (as a percent)				2.66%
Less: unamortized discount and issuance costs				$ (6)
Total debt				$ 619
4.20% Senior Notes due September 15, 2020 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.20%	4.20%		4.20%
Debt, gross	$ 0			$ 750
Effective interest rate (as a percent)				4.25%
New 2.50% Convertible Senior Notes due April 1, 2022 \| Convertible Debt
Debt Instrument [Line Items]
Stated interest rate (as a percent)	2.50%				2.50%	2.50%	2.50%
Debt, gross	$ 250			$ 250
Effective interest rate (as a percent)	2.63%			2.63%
Less: unamortized discount and issuance costs	$ 0			$ (1)
Total debt	$ 250			249
3.95% Senior Notes due June 15, 2022 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as a percent)	3.95%							3.95%
Debt, gross	$ 400			$ 400
Effective interest rate (as a percent)	4.05%			4.05%
New 2.00% Convertible Unsecured Notes due August 15, 2022 \| Convertible Debt
Debt Instrument [Line Items]
Stated interest rate (as a percent)	2.00%		2.00%			2.00%	2.00%
Debt, gross	$ 625			$ 625
Effective interest rate (as a percent)	2.62%			2.62%
Less: unamortized discount and issuance costs	$ (5)			$ (9)
Total debt	620			616
Term Loan due November 4, 2024 \| Unsecured Debt
Debt Instrument [Line Items]
Debt, gross	$ 494			$ 500
Term loan, interest rate	1.50%			2.88%
Delayed Term Loan due November 4, 2024 \| Unsecured Debt
Debt Instrument [Line Items]
Debt, gross	$ 741
Term loan, interest rate	1.50%
5.0% Senior Notes due April 15, 2025 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as a percent)	5.00%							5.00%
Debt, gross	$ 1,100			$ 1,100				$ 1,100
Effective interest rate (as a percent)	5.00%			5.23%
0.95% Avira Mortgage due December 30, 2030 \| Mortgages
Debt Instrument [Line Items]
Stated interest rate (as a percent)	0.95%
Debt, gross	$ 5
Effective interest rate (as a percent)	0.95%
1.29% Avira Mortgage due December 30, 2029 \| Mortgages
Debt Instrument [Line Items]
Stated interest rate (as a percent)	1.29%
Debt, gross	$ 5
Effective interest rate (as a percent)	1.29%