Stockholders' Equity and Stock-Based Compensation - Stock Option Activity (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 29, 2012
Number of Shares (in millions)
Options outstanding at September 28, 2013	14.9
Granted	2.4	2.6	2.3
Canceled/ forfeited	(2.8)
Exercised	(4.7)
Options outstanding at September 27, 2014	9.8	14.9
Options exercisable at September 27, 2014	4.8
Options vested and expected to vest at September 27, 2014 (1)	9.3
Weighted- Average Exercise Price
Options outstanding at September 28, 2013	$ 18.92
Granted	$ 22.01	$ 20.29	$ 17.21
Canceled/ forfeited	$ 22.27
Exercised	$ 15.03
Options outstanding at September 28, 2013	$ 20.59	$ 18.92
Options exercisable at September 27, 2014	$ 21.49
Options vested and expected to vest at September 27, 2014 (1)	$ 20.65
Weighted- Average Remaining Contractual Life (in Years)
Options outstanding at September 28, 2013	4 years 1 month 6 days	3 years 10 months 24 days
Options outstanding at September 27, 2014	4 years 1 month 6 days	3 years 10 months 24 days
Options exercisable at September 27, 2014	2 years 10 months 13 days
Options vested and expected to vest at September 27, 2014 (1)	4 years
Aggregate Intrinsic Value (in millions)
Options outstanding at September 28, 2013	$ 55.0
Exercised	34.7	37.6	20.4
Options outstanding at September 27, 2014	46.4	55.0
Options exercisable at September 27, 2014	23.1
Options vested and expected to vest at September 27, 2014 (1)	$ 44.0