Investments (Summary of Investments) (Details) - USD ($) $ in Millions	Dec. 28, 2019	Jun. 29, 2019
Schedule of Investments [Line Items]
Short-term investments	$ 256.4	$ 253.6
Long-term investments	0.0	0.0
Investments	256.4	253.6
Cash and cash equivalents	896.9	969.2
Other short-term investments	12.8	10.4
Other long-term investments	0.1	0.1
Other investments	12.9	10.5
Cash, cash equivalents, and short-term investments	269.8	264.6
Cash, cash equivalents, and long-term Investments	0.1	0.1
Cash, cash equivalents, and investments	269.9	264.7
Time deposits
Schedule of Investments [Line Items]
Cash and cash equivalents	0.6	0.6
Commercial paper
Schedule of Investments [Line Items]
Short-term investments	0.0	17.9
Long-term investments	0.0	0.0
Investments	0.0	17.9
Government securities - U.S.
Schedule of Investments [Line Items]
Short-term investments	102.9	102.6
Long-term investments	0.0	0.0
Investments	102.9	102.6
Corporate debt securities - U.S.
Schedule of Investments [Line Items]
Short-term investments	109.8	95.8
Long-term investments	0.0	0.0
Investments	109.8	95.8
Corporate debt securities - non U.S.
Schedule of Investments [Line Items]
Short-term investments	43.7	37.3
Long-term investments	0.0	0.0
Investments	$ 43.7	$ 37.3