Changes in Level 3 Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 29, 2012	Oct. 01, 2011
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Beginning Balance	$ 1,229	$ 977
Additions	216	265
Distributions	(142)	(120)
Unrealized Gain (Loss)	21	107
Ending Balance	1,324	1,229
Alternative Investments | Diversified
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Beginning Balance	171	166
Additions	1	7
Distributions	(2)	(6)
Unrealized Gain (Loss)	9	4
Ending Balance	179	171
Alternative Investments | Distressed
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Beginning Balance	228	196
Additions	19	34
Distributions	(52)	(24)
Unrealized Gain (Loss)	(1)	22
Ending Balance	194	228
Alternative Investments | Private equity
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Beginning Balance	492	377
Additions	111	148
Distributions	(65)	(66)
Unrealized Gain (Loss)	7	33
Ending Balance	545	492
Alternative Investments | Venture capital
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Beginning Balance	75	59
Additions	10	10
Distributions	(3)	(3)
Unrealized Gain (Loss)	(4)	9
Ending Balance	78	75
Alternative Investments | Real estate
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Beginning Balance	263	179
Additions	75	66
Distributions	(20)	(21)
Unrealized Gain (Loss)	10	39
Ending Balance	$ 328	$ 263