Fair Value Measurements - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Sep. 24, 2016	Aug. 01, 2012
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Investments, fair value	$ 5,300,000	$ 2,600,000
Borrowed principal under credit agreement	1,000,000,000
Credit Agreement
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Borrowed principal under credit agreement	1,670,000,000		$ 2,500,000,000
Securitization Program
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Borrowed principal under credit agreement	200,000,000
Senior Notes
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair value of debt instrument	1,050,000,000	1,060,000,000
Significant Unobservable Inputs (Level 3)
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Investments, fair value	$ 0	$ 0