Financial Instruments (Cash flow hedges) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 28, 2013	Mar. 31, 2013	Mar. 31, 2012
Cash Flow Hedge [Member]
Summary Of Cash Flow Hedge Activity [Line Items]
Gain (loss) recognized in AOCI		$ (45)	$ 658
Gain (loss) reclassified from AOCI into earnings		(147)	477
Pre-tax gain (loss) included in AOCI related to cash flow hedges of forecasted transactions	724
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	367
Gain Loss Related To Hedge Forecasted Transactions And Firm Commitments That Did Not Occur By End Of Originally Specified Period		insignificant gains and losses	insignificant gains and losses
Maximum term of hedged forecasted transactions		20	21
Hedge ineffectiveness gain (loss)		1	4
Cash Flow Hedge [Member] | Interest Rate Contract [Member]
Summary Of Cash Flow Hedge Activity [Line Items]
Gain (loss) recognized in AOCI		(11)	(27)
Gain (loss) reclassified from AOCI into earnings		(102)	(140)
Cash Flow Hedge [Member] | Foreign Exchange Contract [Member]
Summary Of Cash Flow Hedge Activity [Line Items]
Gain (loss) recognized in AOCI		(34)	685
Gain (loss) reclassified from AOCI into earnings		(45)	617
Net Investment Hedge [Member]
Summary Of Cash Flow Hedge Activity [Line Items]
Hedge ineffectiveness gain (loss)		(166)	(220)
Net Investment Hedge [Member] | Foreign Exchange Contract [Member]
Summary Of Cash Flow Hedge Activity [Line Items]
Gain (loss) recognized in AOCI		2,105	(1,502)
Gain (loss) reclassified from AOCI into earnings		(124)	(10)
Fair Value Hedges [Member]
Summary Of Cash Flow Hedge Activity [Line Items]
Hedge ineffectiveness gain (loss)		$ (29)	$ (105)