National Semiconductor acquisition-related costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended	3 Months Ended								6 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 National [Member]	Mar. 31, 2011 National [Member]	Mar. 31, 2012 National [Member] positions	Mar. 31, 2012 National [Member] Minimum [Member] Y	Mar. 31, 2012 National [Member] Maximum [Member] Y	Mar. 31, 2012 National [Member] Amortization of intangible assets [Member]	Mar. 31, 2011 National [Member] Amortization of intangible assets [Member]	Mar. 31, 2012 National [Member] Retention bonuses [Member]	Mar. 31, 2011 National [Member] Retention bonuses [Member]	Mar. 31, 2012 National [Member] Announced employment reductions [Member]	Mar. 31, 2011 National [Member] Announced employment reductions [Member]	Mar. 31, 2012 National [Member] Announced employment reductions [Member]	Mar. 31, 2012 National [Member] Announced employment reductions [Member] Amount to be paid later in the year [Member]	Mar. 31, 2012 National [Member] Announced employment reductions [Member] Amount expected to be recognized during remainder of year [Member]	Mar. 31, 2012 National [Member] Stock-based compensation [Member]	Mar. 31, 2011 National [Member] Stock-based compensation [Member]	Mar. 31, 2012 National [Member] Transaction costs and other costs [Member]	Mar. 31, 2011 National [Member] Transaction costs and other costs [Member]	Mar. 31, 2012 National [Member] As recorded in Acquisition charges [Member]	Mar. 31, 2011 National [Member] As recorded in Acquisition charges [Member]	Mar. 31, 2012 National [Member] Distributor contract termination recorded in COR [Member]	Mar. 31, 2011 National [Member] Distributor contract termination recorded in COR [Member]	Dec. 31, 2011 National [Member] Distributor contract termination recorded in COR [Member] Distributors
Business Acquisition [Line Items]
Acquisition-related costs	$ 153	$ 2	$ 174	$ 2				$ 81	$ 0	$ 41	$ 0	$ 12	$ 0	$ 40		$ 8	$ 6	$ 0	$ 13	$ 2	$ 153	$ 2	$ 21	$ 0
Identified intangible assets subject to amortization, Weighted Average Useful Life (Years)						2	10
Expected number of jobs to be eliminated					350
Business acquisition, Portion of cost recognized related to announced employment reductions already paid														18
Business acquisition, Portion of cost recognized related to announced employment reductions to be paid in remainder of current fiscal year															$ 22
Business Acquistion, Number of distributors discontinued																									1