Cash and Available-for-Sale Securities' Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value Recorded as Cash and Cash Equivalents or Short-Term or Long-Term Marketable Securities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 28, 2013		Sep. 28, 2013		Dec. 29, 2012	Sep. 29, 2012
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	$ 159,245		$ 147,143
Unrealized Gains	412		414
Unrealized Losses	(815)		(796)
Fair Value	158,842		146,761
Cash and Cash Equivalents	14,077		14,259		16,154	10,746
Short-term marketable securities	26,634		26,287
Long-term marketable securities	118,131		106,215
Cash
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	8,404		8,705
Unrealized Gains	0		0
Unrealized Losses	0		0
Fair Value	8,404		8,705
Cash and Cash Equivalents	8,404		8,705
Short-term marketable securities	0		0
Long-term marketable securities	0		0
Level 1
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	6,281	[1]	5,792	[1]
Unrealized Gains	0	[1]	0	[1]
Unrealized Losses	(248)	[1]	(197)	[1]
Fair Value	6,033	[1]	5,595	[1]
Cash and Cash Equivalents	2,236	[1]	1,793	[1]
Short-term marketable securities	3,797	[1]	3,802	[1]
Long-term marketable securities	0	[1]	0	[1]
Level 1 | Money market funds
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	2,236	[1]	1,793	[1]
Unrealized Gains	0	[1]	0	[1]
Unrealized Losses	0	[1]	0	[1]
Fair Value	2,236	[1]	1,793	[1]
Cash and Cash Equivalents	2,236	[1]	1,793	[1]
Short-term marketable securities	0	[1]	0	[1]
Long-term marketable securities	0	[1]	0	[1]
Level 1 | Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	4,045	[1]	3,999	[1]
Unrealized Gains	0	[1]	0	[1]
Unrealized Losses	(248)	[1]	(197)	[1]
Fair Value	3,797	[1]	3,802	[1]
Cash and Cash Equivalents	0	[1]	0	[1]
Short-term marketable securities	3,797	[1]	3,802	[1]
Long-term marketable securities	0	[1]	0	[1]
Level 2
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	144,560	[2]	132,646	[2]
Unrealized Gains	412	[2]	414	[2]
Unrealized Losses	(567)	[2]	(599)	[2]
Fair Value	144,405	[2]	132,461	[2]
Cash and Cash Equivalents	3,437	[2]	3,761	[2]
Short-term marketable securities	22,837	[2]	22,485	[2]
Long-term marketable securities	118,131	[2]	106,215	[2]
Level 2 | U.S. Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	39,177	[2]	27,642	[2]
Unrealized Gains	11	[2]	24	[2]
Unrealized Losses	(62)	[2]	(47)	[2]
Fair Value	39,126	[2]	27,619	[2]
Cash and Cash Equivalents	629	[2]	431	[2]
Short-term marketable securities	8,498	[2]	7,554	[2]
Long-term marketable securities	29,999	[2]	19,634	[2]
Level 2 | U.S. agency securities
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	16,087	[2]	16,878	[2]
Unrealized Gains	7	[2]	12	[2]
Unrealized Losses	(37)	[2]	(52)	[2]
Fair Value	16,057	[2]	16,838	[2]
Cash and Cash Equivalents	1,016	[2]	177	[2]
Short-term marketable securities	3,854	[2]	3,412	[2]
Long-term marketable securities	11,187	[2]	13,249	[2]
Level 2 | Non-U.S. government securities
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	5,470	[2]	5,545	[2]
Unrealized Gains	25	[2]	35	[2]
Unrealized Losses	(141)	[2]	(137)	[2]
Fair Value	5,354	[2]	5,443	[2]
Cash and Cash Equivalents	0	[2]	50	[2]
Short-term marketable securities	276	[2]	313	[2]
Long-term marketable securities	5,078	[2]	5,080	[2]
Level 2 | Certificates of deposit and time deposits
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	1,438	[2]	2,344	[2]
Unrealized Gains	0	[2]	0	[2]
Unrealized Losses	0	[2]	0	[2]
Fair Value	1,438	[2]	2,344	[2]
Cash and Cash Equivalents	668	[2]	1,264	[2]
Short-term marketable securities	494	[2]	844	[2]
Long-term marketable securities	276	[2]	236	[2]
Level 2 | Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	2,212	[2]	2,998	[2]
Unrealized Gains	0	[2]	0	[2]
Unrealized Losses	0	[2]	0	[2]
Fair Value	2,212	[2]	2,998	[2]
Cash and Cash Equivalents	1,122	[2]	1,835	[2]
Short-term marketable securities	991	[2]	1,163	[2]
Long-term marketable securities	99	[2]	0	[2]
Level 2 | Corporate Securities
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	57,709	[2]	54,586	[2]
Unrealized Gains	297	[2]	275	[2]
Unrealized Losses	(221)	[2]	(252)	[2]
Fair Value	57,785	[2]	54,609	[2]
Cash and Cash Equivalents	2	[2]	0	[2]
Short-term marketable securities	7,658	[2]	8,077	[2]
Long-term marketable securities	50,125	[2]	46,532	[2]
Level 2 | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	6,246	[2]	6,257	[2]
Unrealized Gains	49	[2]	45	[2]
Unrealized Losses	(13)	[2]	(22)	[2]
Fair Value	6,282	[2]	6,280	[2]
Cash and Cash Equivalents	0	[2]	4	[2]
Short-term marketable securities	1,021	[2]	1,114	[2]
Long-term marketable securities	5,261	[2]	5,162	[2]
Level 2 | Mortgage and asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	16,221	[2]	16,396	[2]
Unrealized Gains	23	[2]	23	[2]
Unrealized Losses	(93)	[2]	(89)	[2]
Fair Value	16,151	[2]	16,330	[2]
Cash and Cash Equivalents	0	[2]	0	[2]
Short-term marketable securities	45	[2]	8	[2]
Long-term marketable securities	$ 16,106	[2]	$ 16,322	[2]

[1] The fair value of Level 1 securities is estimated based on quoted prices in active markets for identical assets or liabilities.

[2] The fair value of Level 2 securities is estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.