Fair Value Measurements - Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Jul. 03, 2021	Jun. 27, 2020
Assets:
Short-term investments:	$ 1,171.7	$ 1,255.8
Cash held in bank	128.3	114.2
Certificates of deposit
Assets:
Short-term investments:	28.5	12.9
Commercial paper
Assets:
Short-term investments:	136.7	180.2
Corporate debt securities
Assets:
Short-term investments:	625.9	436.6
Municipal bonds
Assets:
Short-term investments:	1.0
Foreign government bonds
Assets:
Short-term investments:		1.7
U.S. Agency securities
Assets:
Short-term investments:	29.3	59.5
U.S. Treasury securities
Assets:
Short-term investments:	350.3	564.9
Recurring basis
Assets:
Total assets	1,817.7	1,439.6
Recurring basis | Certificates of deposit
Assets:
Short-term investments:	28.5	12.9
Recurring basis | Commercial paper
Assets:
Short-term investments:	136.7	180.2
Recurring basis | Corporate debt securities
Assets:
Short-term investments:	625.9	436.6
Recurring basis | Municipal bonds
Assets:
Short-term investments:	1.0
Recurring basis | Foreign government bonds
Assets:
Short-term investments:		1.7
Recurring basis | U.S. Agency securities
Assets:
Short-term investments:	29.3	59.5
Recurring basis | U.S. Treasury securities
Assets:
Short-term investments:	350.3	564.9
Recurring basis | Commercial paper
Assets:
Cash equivalents:	7.5
Recurring basis | Corporate debt securities
Assets:
Cash equivalents:	7.0
Recurring basis | Money market funds
Assets:
Cash equivalents:	631.5	159.6
Recurring basis | U.S. Treasury securities
Assets:
Cash equivalents:		24.2
Recurring basis | Level 1
Assets:
Total assets	981.8	748.7
Recurring basis | Level 1 | Certificates of deposit
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 1 | Commercial paper
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 1 | Corporate debt securities
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 1 | Municipal bonds
Assets:
Short-term investments:	0.0
Recurring basis | Level 1 | Foreign government bonds
Assets:
Short-term investments:		0.0
Recurring basis | Level 1 | U.S. Agency securities
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 1 | U.S. Treasury securities
Assets:
Short-term investments:	350.3	564.9
Recurring basis | Level 1 | Commercial paper
Assets:
Cash equivalents:	0.0
Recurring basis | Level 1 | Corporate debt securities
Assets:
Cash equivalents:	0.0
Recurring basis | Level 1 | Money market funds
Assets:
Cash equivalents:	631.5	159.6
Recurring basis | Level 1 | U.S. Treasury securities
Assets:
Cash equivalents:		24.2
Recurring basis | Level 2
Assets:
Total assets	835.9	690.9
Recurring basis | Level 2 | Certificates of deposit
Assets:
Short-term investments:	28.5	12.9
Recurring basis | Level 2 | Commercial paper
Assets:
Short-term investments:	136.7	180.2
Recurring basis | Level 2 | Corporate debt securities
Assets:
Short-term investments:	625.9	436.6
Recurring basis | Level 2 | Municipal bonds
Assets:
Short-term investments:	1.0
Recurring basis | Level 2 | Foreign government bonds
Assets:
Short-term investments:		1.7
Recurring basis | Level 2 | U.S. Agency securities
Assets:
Short-term investments:	29.3	59.5
Recurring basis | Level 2 | U.S. Treasury securities
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 2 | Commercial paper
Assets:
Cash equivalents:	7.5
Recurring basis | Level 2 | Corporate debt securities
Assets:
Cash equivalents:	7.0
Recurring basis | Level 2 | Money market funds
Assets:
Cash equivalents:	0.0	0.0
Recurring basis | Level 2 | U.S. Treasury securities
Assets:
Cash equivalents:		0.0
Recurring basis | Level 3
Assets:
Total assets	0.0	0.0
Recurring basis | Level 3 | Certificates of deposit
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 3 | Commercial paper
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 3 | Corporate debt securities
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 3 | Municipal bonds
Assets:
Short-term investments:	0.0
Recurring basis | Level 3 | Foreign government bonds
Assets:
Short-term investments:		0.0
Recurring basis | Level 3 | U.S. Agency securities
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 3 | U.S. Treasury securities
Assets:
Short-term investments:	0.0	0.0
Recurring basis | Level 3 | Commercial paper
Assets:
Cash equivalents:	0.0
Recurring basis | Level 3 | Corporate debt securities
Assets:
Cash equivalents:	0.0
Recurring basis | Level 3 | Money market funds
Assets:
Cash equivalents:	$ 0.0	0.0
Recurring basis | Level 3 | U.S. Treasury securities
Assets:
Cash equivalents:		$ 0.0