Transformation and Other Actions (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Jun. 27, 2015
Restructuring Reserve [Roll Forward]
Restructuring charges	$ 2.8	$ 13.2
2014 Transformation Plan
Restructuring Reserve [Roll Forward]
Balance at beginning of period	17.8	22.5	$ 22.5
Restructuring charges	12.6	37.1	145.9
Cash payments	(11.3)		(90.9)
Non-cash adjustments	(5.4)		(59.7)
Balance at end of period	13.7		17.8
2014 Transformation Plan | Inventory-Related Charges
Restructuring Reserve [Roll Forward]
Balance at beginning of period	0.0	15.4	15.4
Restructuring charges	0.0		3.0
Cash payments	0.0		(15.4)
Non-cash adjustments	0.0		(3.0)
Balance at end of period	0.0		0.0
2014 Transformation Plan | Store-Related Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period	2.5	5.5	5.5
Restructuring charges	5.1		80.4
Cash payments	(1.8)		(34.6)
Non-cash adjustments	(4.6)		(48.8)
Balance at end of period	1.2		2.5
2014 Transformation Plan | Organizational Efficiency Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period	12.0	1.0	1.0
Restructuring charges	6.5		47.3
Cash payments	(9.4)		(30.8)
Non-cash adjustments	0.0		(5.5)
Balance at end of period	9.1		12.0
2014 Transformation Plan | Other
Restructuring Reserve [Roll Forward]
Balance at beginning of period	3.3	$ 0.6	0.6
Restructuring charges	1.0		15.2
Cash payments	(0.1)		(10.1)
Non-cash adjustments	(0.8)		(2.4)
Balance at end of period	$ 3.4		$ 3.3