Receivables (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Receivables
Accounts receivable	$ 8,650	$ 8,061
Commodity derivative and foreign currency contract receivables	98	136
Notes receivable and other	49	26
Receivables, gross	8,797	8,223
Allowance for doubtful accounts	(46)	(56)	(48)
Receivables, net	8,751	8,167
Movement in Valuation Allowances and Reserves Rollforward
Balance as of beginning of year	56	48	42
Increase in allowance charged to expense	13	21	21
Accounts charged against the allowance, net of recoveries	(23)	(13)	(14)
Foreign currency translation	0	0	(1)
Balance as of end of year	$ 46	$ 56	$ 48